CN114197048B - Monocrystalline film with two-dimensional electron gas and preparation method thereof - Google Patents
Monocrystalline film with two-dimensional electron gas and preparation method thereof Download PDFInfo
- Publication number
- CN114197048B CN114197048B CN202111490995.0A CN202111490995A CN114197048B CN 114197048 B CN114197048 B CN 114197048B CN 202111490995 A CN202111490995 A CN 202111490995A CN 114197048 B CN114197048 B CN 114197048B
- Authority
- CN
- China
- Prior art keywords
- film
- latio
- dimensional electron
- electron gas
- single crystal
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
- 230000005533 two-dimensional electron gas Effects 0.000 title claims abstract description 26
- 238000002360 preparation method Methods 0.000 title abstract description 8
- 239000010408 film Substances 0.000 claims abstract description 75
- 239000000758 substrate Substances 0.000 claims abstract description 29
- 239000010409 thin film Substances 0.000 claims abstract description 28
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 26
- 239000001301 oxygen Substances 0.000 claims abstract description 26
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 26
- 239000013078 crystal Substances 0.000 claims abstract description 22
- 229910002367 SrTiO Inorganic materials 0.000 claims abstract description 21
- 239000013077 target material Substances 0.000 claims abstract description 15
- MRELNEQAGSRDBK-UHFFFAOYSA-N lanthanum(3+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[La+3].[La+3] MRELNEQAGSRDBK-UHFFFAOYSA-N 0.000 claims abstract description 14
- 238000000151 deposition Methods 0.000 claims abstract description 13
- 230000008021 deposition Effects 0.000 claims abstract description 11
- 239000000843 powder Substances 0.000 claims abstract description 10
- 238000005530 etching Methods 0.000 claims abstract description 8
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000000227 grinding Methods 0.000 claims abstract description 7
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 claims abstract description 7
- 238000004140 cleaning Methods 0.000 claims abstract description 6
- 238000003825 pressing Methods 0.000 claims abstract description 6
- 238000005245 sintering Methods 0.000 claims abstract description 6
- 238000002156 mixing Methods 0.000 claims abstract description 5
- 239000002243 precursor Substances 0.000 claims abstract description 5
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 9
- CSCPPACGZOOCGX-UHFFFAOYSA-N Acetone Chemical compound CC(C)=O CSCPPACGZOOCGX-UHFFFAOYSA-N 0.000 claims description 8
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 6
- 239000008367 deionised water Substances 0.000 claims description 5
- 229910021641 deionized water Inorganic materials 0.000 claims description 5
- 238000000034 method Methods 0.000 claims description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 5
- 239000010936 titanium Substances 0.000 description 10
- 239000000919 ceramic Substances 0.000 description 8
- 239000012212 insulator Substances 0.000 description 6
- 238000004549 pulsed laser deposition Methods 0.000 description 6
- 238000012360 testing method Methods 0.000 description 6
- 239000011812 mixed powder Substances 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- 238000001816 cooling Methods 0.000 description 4
- 238000001035 drying Methods 0.000 description 4
- 238000004506 ultrasonic cleaning Methods 0.000 description 4
- NIPNSKYNPDTRPC-UHFFFAOYSA-N N-[2-oxo-2-(2,4,6,7-tetrahydrotriazolo[4,5-c]pyridin-5-yl)ethyl]-2-[[3-(trifluoromethoxy)phenyl]methylamino]pyrimidine-5-carboxamide Chemical compound O=C(CNC(=O)C=1C=NC(=NC=1)NCC1=CC(=CC=C1)OC(F)(F)F)N1CC2=C(CC1)NN=N2 NIPNSKYNPDTRPC-UHFFFAOYSA-N 0.000 description 3
- 238000000137 annealing Methods 0.000 description 3
- 230000000694 effects Effects 0.000 description 3
- 238000005516 engineering process Methods 0.000 description 3
- 235000019441 ethanol Nutrition 0.000 description 3
- 238000011160 research Methods 0.000 description 3
- 238000001228 spectrum Methods 0.000 description 3
- 230000007704 transition Effects 0.000 description 3
- 244000137852 Petrea volubilis Species 0.000 description 2
- 230000005290 antiferromagnetic effect Effects 0.000 description 2
- 230000008859 change Effects 0.000 description 2
- 239000004020 conductor Substances 0.000 description 2
- 238000010304 firing Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 230000008569 process Effects 0.000 description 2
- 239000000523 sample Substances 0.000 description 2
- 238000003756 stirring Methods 0.000 description 2
- 238000009423 ventilation Methods 0.000 description 2
- 238000004458 analytical method Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 239000011230 binding agent Substances 0.000 description 1
- 238000012512 characterization method Methods 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 230000001276 controlling effect Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 230000001747 exhibiting effect Effects 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- LSYIMYXKHWXNBV-UHFFFAOYSA-N lanthanum(3+) oxygen(2-) titanium(4+) Chemical compound [O-2].[La+3].[Ti+4] LSYIMYXKHWXNBV-UHFFFAOYSA-N 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 230000003647 oxidation Effects 0.000 description 1
- 238000007254 oxidation reaction Methods 0.000 description 1
- -1 polytetrafluoroethylene Polymers 0.000 description 1
- 229920001343 polytetrafluoroethylene Polymers 0.000 description 1
- 239000004810 polytetrafluoroethylene Substances 0.000 description 1
- 230000009467 reduction Effects 0.000 description 1
- 230000001105 regulatory effect Effects 0.000 description 1
- 230000009897 systematic effect Effects 0.000 description 1
- 238000009210 therapy by ultrasound Methods 0.000 description 1
- 238000002233 thin-film X-ray diffraction Methods 0.000 description 1
- 238000012546 transfer Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
- C30B29/10—Inorganic compounds or compositions
- C30B29/16—Oxides
- C30B29/22—Complex oxides
- C30B29/32—Titanates; Germanates; Molybdates; Tungstates
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
- C30B23/002—Controlling or regulating
-
- C—CHEMISTRY; METALLURGY
- C30—CRYSTAL GROWTH
- C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
- C30B23/00—Single-crystal growth by condensing evaporated or sublimed materials
- C30B23/02—Epitaxial-layer growth
Landscapes
- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Crystallography & Structural Chemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Inorganic Chemistry (AREA)
- Crystals, And After-Treatments Of Crystals (AREA)
Abstract
The invention discloses a preparation method of a monocrystalline film with two-dimensional electron gas, which comprises the following steps: (1) Uniformly mixing lanthanum oxide and titanium oxide precursor powder, grinding, pressing a target by a tablet press, and sintering at high temperature in a muffle furnace to obtain LaTiO 3 A target material; (2) Cleaning and etching SrTiO 3 A substrate; (3) LaTiO 3 Target and treated SrTiO 3 Placing the substrates together into a pulse laser deposition system to grow LaTiO under proper conditions 3 A single crystal thin film; (4) Obtaining LaTiO with the same thickness at different temperatures under a vacuum environment 3 A film; (5) Controlling different oxygen pressures, reducing the vacuum degree which can be achieved when the film grows from high vacuum to low vacuum, growing a film every other order of magnitude, and preparing LaTiO under different oxygen pressures 3 A film. According to the invention, two-dimensional electron gas exists between the film and the STO interface through the curve, so that the film shows metallic appearance.
Description
Technical Field
The invention belongs to the field of Pulsed Laser Deposition (PLD) technology and perovskite oxide film preparation, and in particular relates to a LaTiO with two-dimensional electron gas 3 A single crystal thin film and a method for producing the same.
Background
LaTiO in Mott insulator 3 SrTiO for tape-like insulator 3 The two-dimensional electron gas (2 DEG) in between has led to extensive research in the last decade, but the physical origin of this phenomenon remains controversial. When epitaxial film LaAlO 3 /SrTiO 3 Two-dimensional electron gas in the interface was studied in a large amount since the first report of Ohtomo in 2004, and the two-dimensional electron gas was inLaTiO 3 /SrTiO 3 (001) This has been found to be more of a cause for human versus LaTiO 3 There is great interest in epitaxial thin film research. Numerous studies have shown that Ti has d0 state in the general titanates, however the antiferromagnetic Mott insulator LaTiO 3 In which Ti is in d1 form, especially when LaTiO 3 Epitaxially grown SrTiO in (001) crystallographic orientation 3 When the substrate is coated, an interface conductive layer with two-dimensional electron gas appears, thereby leading the LaTiO to be 3 Exhibiting metallic characteristics.
However, with LaTiO 3 /SrTiO 3 (001) There are many views of the change in Ti electronic structure, and some believe that Ti transitions from a Mott insulator in the 3d1 state to a conductor in the 3d0 state due to epitaxial stress. While others believe this transition is an interface effect caused by charge transfer at the epitaxial interface. However, to cause LaTiO 3 /SrTiO 3 (001) The root cause of the transition of Ti from Mott insulator in 3d1 state to conductor in 3d0 state remains under debate.
However, laTiO for different growth temperatures and different oxygen pressures 3 /SrTiO 3 Research of monocrystalline film and such LaTiO 3 /SrTiO 3 The presence or absence of 2DEG in the film is currently known and has not been reported by systematic studies.
Disclosure of Invention
Aiming at the defects existing in the prior art, the invention provides a LaTiO with two-dimensional electron gas 3 A single crystal thin film and a method for producing the same.
In order to achieve the above object, the present invention adopts the following technical scheme:
a monocrystalline film with two-dimensional electron gas and a preparation method thereof comprise the following steps:
(1) Uniformly mixing lanthanum oxide and titanium oxide precursor powder in proportion, grinding, pressing a target by a tablet press, and sintering at high temperature in a muffle furnace to obtain LaTiO 3 A target material;
(2) Cleaning and etching SrTiO 3 A substrate;
(3) LaTiO 3 Target and treated SrTiO 3 The substrates are put into pulse laser togetherPhoto-deposition system for growing LaTiO under proper condition 3 A single crystal thin film;
(4) Obtaining LaTiO with the same thickness at different temperatures under a vacuum environment 3 A film;
(5) Controlling different oxygen pressures, reducing the vacuum degree which can be achieved when the film grows from high vacuum to low vacuum, growing a film every other order of magnitude, and preparing LaTiO under different oxygen pressures 3 A film.
Further, in step (1): due to Ti 3+ Is easily oxidized, and firing LaTiO is performed in an environment of high temperature and air exposure 3 The ceramic target material can only obtain Ti 4+ LaTiO of (C) 3.5 Phase targets, however, the presence of excess oxygen in the target is not relevant to growing LaTiO for PLD systems 3 The film is affected because the invention only needs to grow LaTiO 3 The environment of the film is high vacuum, the mol ratio of lanthanum oxide to titanium oxide in the target material is 1:2, and oxygen can be regulated by the growth environment, so the LaTiO is prepared by the invention 3.5 Phase ceramic targets for growth of LaTiO 3 An epitaxial thin film. Firstly grinding lanthanum oxide and titanium oxide precursor powder according to a certain proportion for 30min for half an hour, adding 10ml of absolute ethyl alcohol into the mixed powder, stirring and grinding in the process, and then putting the mixed powder into a drying oven at 60 ℃ for ventilation drying for 30min to obtain fully mixed powder. Grinding the dried mixed powder for 2min, adding 10ml of absolute ethanol, stirring, grinding for 15min again, and volatilizing ethanol completely by ventilation. And then placing the obtained mixed powder into a crucible, and placing the crucible into a muffle furnace to heat to 1200-1250 ℃ to obtain lanthanum titanium oxide powder. Cooling, placing the powder into a cleaned mold, and maintaining at 12Mpa for 10min to obtain LaTiO with diameter of 1 inch and thickness of 4mm 3 Pre-sintering the target. Finally, the presintered target material is put into a muffle furnace to be fired for 12 hours at 1300-1350 ℃ to obtain compact LaTiO 3.5 A ceramic target.
Further, in the step (2), firstly, acetone is used for ultrasonic cleaning for 5-10min, then absolute ethyl alcohol is used for ultrasonic cleaning for 5-10min, finally deionized water is used for cleaning for 5-10min, and nitrogen is used for drying, so that the STO substrate with the clean surface is obtained. Etching the cleaned substrate, firstly adding a proper amount of BOE solution into a polytetrafluoroethylene beaker, and etching the STO substrate solution for 10-15 s; then placing the substrate into deionized water for ultrasonic cleaning for 5-10min, and removing residual BOE solution on the surface of the substrate; and drying with nitrogen to obtain the etched STO substrate. And then annealing at 1000 ℃ for 60min and cooling to room temperature at the same rate to obtain the etched STO substrate.
Further, depositing LaTiO in step (3) 3 When different deposition temperatures of 550 ℃ to 800 ℃ and different gas pressures (10 -7 Torr) to 10 -3 Torr, energy density during growth was 1.5 J.cm -2 。
Further, the samples at different temperatures of 550 to 800 ℃ are grown in the high vacuum environment in the step (4) and the step (5), and LaTiO at 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃ and 800 ℃ are grown at intervals of 50 ℃ respectively 3 Film, determined to be LaTiO at 650 DEG C 3 Optimum growth temperature of the film, followed by growth at optimum growth temperature from high vacuum (10 -7 Torr) to 10 -3 LaTiO under Torr 3 Thin films, one on every order of magnitude, were grown, and high vacuum (0 Torr) was determined to be LaTiO in accordance with the same method of characterizing the structure 3 Optimal grown oxygen partial pressure of the film.
Compared with the prior art, the invention has the following beneficial effects:
the invention aims to provide the LaTiO with two-dimensional electron gas 3 Compared with other film preparation technologies, the preparation method of the monocrystalline film can prepare a high-quality film by the pulse laser deposition technology, so that the prepared LaTiO 3 The epitaxial film material is a single crystal film and has excellent two-dimensional electron gas properties, and is used for researching LaTiO 3 Provides high quality film samples.
Drawings
FIG. 1 shows the LaTiO obtained in example 1 3.5 XRD spectrum of ceramic target;
FIG. 2 shows the LaTi at different temperatures according to example 1O 3 A thin film XRD diffractogram;
FIG. 3 shows LaTiO grown at different temperatures according to example 1 3 A thin film R-T curve;
FIG. 4 shows LaTiO grown with different oxygen partial pressures in example 1 3 Film XRD;
FIG. 5 shows LaTiO grown at different oxygen partial pressures in example 1 3 Film R-T curve.
Detailed Description
The following describes the embodiments of the present invention in detail with reference to the drawings.
In an embodiment, the LaTiO with two-dimensional electron gas 3 A method for producing a single crystal thin film, comprising the steps of:
(1) Firing the target: firstly mixing lanthanum oxide and titanium oxide according to the mol ratio of 1:2, placing into a muffle furnace for presintering for 12 hours at 1200-1250 ℃, cooling, placing the powder into a cleaned mould, and maintaining at 12Mpa for 10min to obtain LaTiO with the diameter of 1 inch and the thickness of 4mm 3 Presintered target material; finally, the presintered target material is put into a muffle furnace to be fired for 12 hours at 1300-1350 ℃ to obtain compact LaTiO 3 Finally polishing the burned target material by sand paper to obtain the LaTiO for pulse laser deposition 3 A ceramic;
(2) SrTiO 3 Sequentially placing the substrate into acetone, alcohol and deionized water, and performing ultrasonic treatment and cleaning for 5min, 5min and 10min respectively; etching the substrate for 10-15s by using hydrofluoric acid diluted by 10:1, and annealing the etched substrate in a tube furnace at 1000 ℃ for 1h;
(3) LaTiO 3 Target and treated SrTiO 3 The substrates are put into a pulse laser deposition system together and SrTiO is carried out under proper conditions 3 Epitaxial growth of LaTiO on a substrate 3 A single crystal thin film;
(4) For temperature selection, under high vacuum, the invention grows LaTiO with the same thickness at different temperatures of 550-800 ℃ at 50 ℃ as temperature interval 3 The thickness of the film is about 12nm, and the LaTiO with different temperatures is prepared 3 A single crystal thin film;
(5) At 650 DEG CLaTiO under different oxygen partial pressures is grown 3 Setting of the oxygen partial pressure of epitaxial thin film the invention changes the vacuum from high vacuum (10 depending on the vacuum degree that PLD equipment can achieve when thin film is grown -7 Torr) to 10 -3 A film grows at every other order of magnitude of Torr to obtain LaTiO under different oxygen pressures 3 A single crystal thin film.
The following is a description of more specific embodiments.
Example 1
A preparation method of a monocrystalline film with two-dimensional electron gas comprises the following steps:
(1) Firstly mixing lanthanum oxide and titanium oxide according to the mol ratio of 1:2, placing into a muffle furnace for presintering for 12 hours at 1200-1250 ℃, cooling, placing the powder into a cleaned mould, and maintaining at 12Mpa for 10min to obtain LaTiO with the diameter of 1 inch and the thickness of 4mm 3 Presintered target material; finally, the presintered target material is put into a muffle furnace to be fired for 12 hours at 1300-1350 ℃ to obtain compact LaTiO 3 Finally polishing the burned target material by sand paper to obtain the LaTiO for pulse laser deposition 3 A ceramic;
(2) SrTiO 3 Sequentially placing the substrate into acetone, alcohol and deionized water for cleaning for 5min, 5min and 10min respectively; etching the substrate for 10-15s by using hydrofluoric acid diluted by 10:1, and annealing for 1h in a tube furnace at 1000 ℃;
(3) LaTiO 3 Target and treated SrTiO 3 The substrate is put into a pulse laser deposition system together with SrTiO 3 Epitaxial growth of LaTiO on a substrate 3 A single crystal thin film; deposition of LaTiO 3 The temperature is 550-800 ℃ and the air pressure is 10 -7 -10 -3 torr, energy density of 1.5 J.cm -2 。
(4) In a high vacuum (10) -7 Torr), energy density of 1.5 J.cm -2 At the same time, laTiO with the same thickness at different temperatures of 550-800 ℃ is grown at 50 ℃ as the temperature interval 3 The thickness of the film is about 12 nm;
(5) At a temperature of 650 ℃, the energy density is 1.5 J.cm -2 LaTiO at different oxygen partial pressures is grown 3 Setting of the oxygen partial pressure of epitaxial thin film the invention changes the vacuum from high vacuum (10 depending on the vacuum degree that PLD equipment can achieve when thin film is grown -7 Torr) to 10 -3 A film grows at every other order of magnitude of Torr to obtain LaTiO under different oxygen pressures 3 A single crystal thin film.
LaTiO grown under different oxygen pressures and different temperatures 3 The epitaxial film was tested for electrical transport performance using 4200-SCS system and wire bonder apparatus to connect leads, and LaTiO was tested 3 The resistance curve of the film investigated the effect of two-dimensional electron gas between the film and the substrate.
The testing resistor is mainly characterized in that a four-probe method is used for testing the resistivity of a film, a wire binder device is used for film connection of pins, and overlong leads need to be prevented from contacting other pins or other parts of a low-temperature cavity liner in the connection process, so that wiring circuit breaking is prevented; after the low-temperature cavity sample rack shell is installed, whether air leakage occurs or not needs to be checked, so that the vacuum degree in the low-temperature cavity is ensured, and test data are reliable and accurate.
Test examples
The LaTiO prepared in example 1 was subjected to powder crystal XRD 3.5 Target material, by LaTiO of figure 1 3.5 XRD results of ceramic targets and LaTiO 3.5 Comparison of standard card PDF#42-0517 can determine burned LaTiO 3.5 No diffraction peak of other phases appears in the ceramic target material, and in the XRD spectrum, the intensity of the diffraction peak is high, the diffraction peak is sharp and the half-width is smaller, which indicates that the prepared LaTiO 3.5 The target material has very good crystallinity and can be used for PLD system to carry out LaTiO 3 Epitaxial growth of thin films.
FIG. 2 to further understand the temperature versus LaTiO 3 Effect of epitaxial films the present invention performed single crystal XRD characterization of the 6 films at different temperatures (550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃) to obtain the results shown in figure 2 below. As can be seen from XRD results, the thin film peak is to the left of the substrate diffraction peak, and only when LaTiO is grown 3 The diffraction peak of the film only appears when the temperature of the film is above 600 ℃, and the diffraction peak of the film except the (001), (002) and (003) planes correspond to each other at 600 and 650 DEG CBesides the diffraction peak of the substrate, the left side of the epitaxial film has a very obvious diffraction peak, which indicates that the single crystal orientation is good. In summary, the present invention considers that the temperature is LaTiO at around 600 ℃ to 650 ℃ under high vacuum 3 Optimal growth temperature properties of the film. FIG. 3 shows the LaTiO obtained at different growth temperatures (600 ℃, 650 ℃, 700 ℃, 750 ℃, 800 ℃) 3 As can be seen from the study of the R-T curve change of the film, the conductivity at the interface between the film and the substrate is enhanced along with the reduction of the test temperature, and the characteristic of two-dimensional electron gas is shown, the invention has obtained that the temperature is 600-650 ℃ which is the optimal temperature, and LaTi growing at 600 ℃ is obtained by testing the R-T curve 3+ The O3 film has a resistance measured at different temperatures greater than that of a film grown at higher temperatures and increases with growth temperature and with Ti in the film 4+ The content of (2) appears, and the film conductivity is better and better, and LaTiO is obtained by growth 3 The film has two-dimensional electron gas with interface, so that the antiferromagnetic Mott insulator LaTiO 3 The material exhibits metallic characteristics.
FIG. 4 shows the oxygen partial pressure (10 -7 Torr、10 -6 Torr、10 -5 Torr、10 -4 Torr、10 -3 Torr) grown LaTiO 3 As can be seen from the full spectrum of the film XRD, the diffraction peak of the film becomes weaker and the peak of the film becomes wider as the oxygen partial pressure increases, up to 10 -3 The peak of the film had substantially disappeared at Torr, indicating that as the oxygen partial pressure in the growth environment became larger, the crystallinity of the film became worse, 10 of them -7 The best results are obtained by XRD of the Torr-grown film.
FIG. 5 is 10 -7 Torr to 10 -3 LaTiO grown under Torr with different oxygen partial pressures 3 From the graph of the R-T curve of the film, it can be seen that as the partial pressure of oxygen used during film deposition increases, the film resistance also increases overall. By comparison, it was found that, under high vacuum (10 -7 Torr) is preferred. The presence of excess oxygen will cause Ti to 3+ Oxidation to Ti 4+ Thereby changing LaTiO 3 The electronic structure of the film is such that it is only exposed to high vacuum (10 -7 Torr) is used to grow the perovskite-structured LaTiO 3 The film is formed by a film-type coating,making LaTiO 3 Two-dimensional electron gas is generated between the film and the substrate and exhibits metallic characteristics.
The foregoing describes in detail preferred embodiments of the present invention. It should be understood that numerous modifications and variations can be made in accordance with the concepts of the invention without requiring creative effort by one of ordinary skill in the art. Therefore, all technical solutions which can be obtained by logic analysis, reasoning or limited experiments based on the prior art by the person skilled in the art according to the inventive concept shall be within the scope of protection defined by the claims.
Claims (7)
1. A method for producing a single crystal thin film having two-dimensional electron gas, comprising the steps of:
(1) Uniformly mixing lanthanum oxide and titanium oxide precursor powder according to a molar ratio of 1:2, grinding, pressing a target by a tablet press, and sintering at high temperature in a muffle furnace to obtain LaTiO 3 A target material;
(2) Cleaning and etching SrTiO 3 A substrate;
(3) LaTiO 3 Target and treated SrTiO 3 Placing the substrates together into a pulse laser deposition system to grow LaTiO under proper conditions 3 A single crystal thin film;
(4) At 10 -7 Obtaining LaTiO with the same thickness at different temperatures under the Torr high vacuum environment 3 A film;
(5) Controlling different oxygen pressures, reducing the vacuum degree which can be achieved when the film grows from high vacuum to low vacuum, growing a film every other order of magnitude, and preparing LaTiO under different oxygen pressures 3 A film;
deposition of LaTiO in step (3) 3 The temperature is 650 ℃, and the air pressure is 10 -7 Torr, energy density of 1.5J cm -2 ；
Step (4) and step (5) are performed by growing samples at different temperatures of 550 ℃ to 800 ℃ in a high vacuum environment, wherein the samples are grown at 50 ℃ every time, and LaTiO at 550 ℃, 600 ℃, 650 ℃, 700 ℃, 750 ℃ and 800 ℃ are grown respectively 3 Film, determined to be LaTiO at 650 DEG C 3 Optimum growth temperature of the film, followed by growth from high vacuum degree 10 at the optimum growth temperature - 7 Torr to 10 -3 LaTiO under Torr 3 Film, one film grown every other order of magnitude, high vacuum 10 was determined -7 Torr is LaTiO 3 Optimal grown oxygen partial pressure of the film.
2. The method for producing a single crystal thin film with two-dimensional electron gas according to claim 1, wherein the mixed precursor powder is ground for 30 to 40 minutes in step (1).
3. The method for producing a single crystal thin film with two-dimensional electron gas according to claim 1, wherein the pressure of the pressing target of the tablet press in the step (1) is 20 to 25 MPa, the pressing time is 10 to 20min, and the size of the die for pressing the target is 1 inch.
4. The method for producing a single crystal thin film with two-dimensional electron gas according to claim 1, wherein the sintering temperature in the step (1) is 1300-1350 ℃ and the sintering time period is 12 hours.
5. The method for producing a single crystal thin film with two-dimensional electron gas according to claim 1, wherein the SrTiO is washed with acetone, alcohol, deionized water in this order in the step (2) 3 The cleaning time of the substrate is 5min, 5min and 10min respectively.
6. The method for producing a single crystal thin film with two-dimensional electron gas according to claim 1, wherein the etching time of the hydrofluoric acid diluted with 10:1 in the step (2) is 10-15s.
7. A single crystal thin film with two-dimensional electron gas prepared according to the method of any one of claims 1 to 6.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111490995.0A CN114197048B (en) | 2021-12-08 | 2021-12-08 | Monocrystalline film with two-dimensional electron gas and preparation method thereof |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202111490995.0A CN114197048B (en) | 2021-12-08 | 2021-12-08 | Monocrystalline film with two-dimensional electron gas and preparation method thereof |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN114197048A CN114197048A (en) | 2022-03-18 |
| CN114197048B true CN114197048B (en) | 2024-04-09 |
Family
ID=80651293
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN202111490995.0A Active CN114197048B (en) | 2021-12-08 | 2021-12-08 | Monocrystalline film with two-dimensional electron gas and preparation method thereof |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN114197048B (en) |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114678587A (en) * | 2022-04-12 | 2022-06-28 | 湖州南木纳米科技有限公司 | Method for preparing solid electrolyte, lanthanum titanium oxide compound and preparation method thereof |
| CN115652258A (en) * | 2022-11-17 | 2023-01-31 | 电子科技大学长三角研究院(湖州) | Amorphous film with good electric transport performance and preparation method thereof |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101752027A (en) * | 2010-02-09 | 2010-06-23 | 中国科学院长春光学精密机械与物理研究所 | Indium lanthanum titanium oxide transparent conductive film |
| CN102864410A (en) * | 2012-08-31 | 2013-01-09 | 西北工业大学 | Preparation method of high dielectric constant gate dielectric lanthanum titanium oxide amorphous film |
| CN103290454A (en) * | 2012-02-28 | 2013-09-11 | 广东技术师范学院 | Method for improving surface morphologies of BaTiO3 and SrTiO3 dielectric films prepared by micro-arc oxidation technology |
-
2021
- 2021-12-08 CN CN202111490995.0A patent/CN114197048B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN101752027A (en) * | 2010-02-09 | 2010-06-23 | 中国科学院长春光学精密机械与物理研究所 | Indium lanthanum titanium oxide transparent conductive film |
| CN103290454A (en) * | 2012-02-28 | 2013-09-11 | 广东技术师范学院 | Method for improving surface morphologies of BaTiO3 and SrTiO3 dielectric films prepared by micro-arc oxidation technology |
| CN102864410A (en) * | 2012-08-31 | 2013-01-09 | 西北工业大学 | Preparation method of high dielectric constant gate dielectric lanthanum titanium oxide amorphous film |
Non-Patent Citations (2)
| Title |
|---|
| "High-Throughput Design of Two-Dimensional Electron Gas Systems Based on Polar/Nonpolar Perovskite Oxide Heterostructures";Kesong Yang等;《Scientific Reports》;20161006;第6卷;34667 * |
| "LaTiO3(110) 薄膜分子束外延生长的精确控制和表面截止层的研究";李文涛等;《物理学报》;20150731;第64卷(第7期);078103 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN114197048A (en) | 2022-03-18 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN114197048B (en) | Monocrystalline film with two-dimensional electron gas and preparation method thereof | |
| Li et al. | Preparation of perovskite conductive LaNiO3 films by metalorganic decomposition | |
| CN100365160C (en) | Preparation method of low resistivity metal oxide lanthanum nickelate | |
| CN103833416B (en) | A kind of chemical solution deposition preparation method of the sour lanthanum conductive film of nickel | |
| CN109487220B (en) | Nickel oxide-lead zirconate antiferroelectric composite film and preparation method thereof | |
| CN103993285A (en) | Preparation method of flexible BMN thin film voltage-controlled varactor | |
| CN110106485B (en) | Negative temperature coefficient thermosensitive film and preparation method thereof | |
| CN101712549B (en) | Method for preparing lanthanum nickel oxide ceramic target | |
| CN111676456A (en) | Self-assembled Ba (Hf, Ti) O3:HfO2Nano composite lead-free epitaxial single-layer film and preparation method thereof | |
| CN107946459A (en) | A kind of whole soln preparation method of oxide memristor | |
| CN113698205B (en) | Composite thermistor material based on rare earth nickel-based oxide and preparation method and application thereof | |
| CN115652258A (en) | Amorphous film with good electric transport performance and preparation method thereof | |
| Kukuruznyak et al. | Preparation and properties of thermistor thin-films by metal organic decomposition | |
| CN101343729A (en) | Method for preparing lanthanum nickelate conductive metallic oxide nano-film | |
| CN110724922B (en) | Epitaxial AZO film with controllable crystal orientation and polarity on flexible substrate and preparation method thereof | |
| CN105296946B (en) | A kind of the bismuth niobate calcium thin film material system and preparation method height-oriented with a axles | |
| Li et al. | Conductive metallic LaNiO3 films from metallo-organic precursors | |
| Fang et al. | Microstructure and dielectric properties of pulsed-laser-deposited CaCu 3 Ti 4 O 12 thin films on LaNiO 3 buffered Pt/Ti/SiO 2/Si substrates | |
| CN109234678B (en) | Copper-doped barium titanate/nickel zinc ferrite multiphase film material and preparation method thereof | |
| JP5136986B2 (en) | Piezoelectric manufacturing method and piezoelectric element | |
| CN107059119B (en) | Method for preparing polycrystalline SiC film through sapphire substrate | |
| CN106653569A (en) | Preparation method of semiconductor material beta-SiC film | |
| CN114267491A (en) | Sol-gel method for preparing high-temperature flexible LaNiO3Method for conductive film | |
| CN109797367B (en) | Lead zirconate titanate/nickel iron oxide electric superlattice thin film material and preparation method thereof | |
| CN104532186A (en) | Method for preparing BTS film by virtue of radio frequency magnetron sputtering |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |