阅读说明：本技术 一种基于GaSe/InSe异质结的光存储、电存储复合型器件及其制备方法 (Optical storage and electric storage composite device based on GaSe/InSe heterojunction and preparation method thereof ) 是由 李洋 孙昭媛 赵泽 徐成彦 甄良 于 2021-09-28 设计创作，主要内容包括：一种基于GaSe/InSe异质结的光存储、电存储复合型器件及其制备方法,属于电子和光电子领域。所述复合型器件包括金属、二维硒化铟、二维硒化镓、栅极介质层。本发明器件采用但不限于机械剥离的方法获得二维纳米片,器件自下而上分别为栅极介质层、二维硒化镓和二维硒化铟层,金属电极与二维硒化铟层接触,金属电极采用但不限于热蒸镀的方法制备。本发明通过调节异质结界面处的能带排列及电荷转移的方式,构筑同时兼备电存储、光存储的GaSe/InSe多功能器件,具有永久光电流和负光电导存储特性,简化了器件结构,实现功能器件的集成。(A composite device of optical storage and electric storage based on GaSe/InSe heterojunction and a preparation method thereof belong to the field of electronics and photoelectron. The composite device comprises metal, two-dimensional indium selenide, two-dimensional gallium selenide and a grid dielectric layer. The device of the invention adopts a method without limitation to mechanical stripping to obtain two-dimensional nanosheets, the device is respectively provided with a grid dielectric layer, a two-dimensional gallium selenide layer and a two-dimensional indium selenide layer from bottom to top, a metal electrode is in contact with the two-dimensional indium selenide layer, and the metal electrode is prepared by a method without limitation to thermal evaporation. The invention constructs a GaSe/InSe multifunctional device which simultaneously has electric storage and optical storage by adjusting the energy band arrangement and charge transfer at the heterojunction interface, has permanent photocurrent and negative photoconduction storage characteristics, simplifies the structure of the device and realizes the integration of functional devices.)

1. A kind of light based on GaSe/InSe heterojunction, electric storage composite type device, characterized by that: the composite device comprises two metal electrodes, two-dimensional indium selenide, two-dimensional gallium selenide and a grid dielectric layer; the device is respectively provided with a grid dielectric layer, a two-dimensional gallium selenide layer and a two-dimensional indium selenide layer from bottom to top, two metal electrodes are arranged on the two-dimensional indium selenide layer and are in contact with the two metal electrodes, a channel is arranged between the metal electrodes, and the width of the channel is 5-30 mu m.

2. The device of claim 1, wherein the device is a composite device for optical storage and electrical storage based on GaSe/InSe heterojunction, and comprises: the gate dielectric layer is made of SiO₂、HfO₂、Al₂O₃And sapphire.

3. The device of claim 1, wherein the device is a composite device for optical storage and electrical storage based on GaSe/InSe heterojunction, and comprises: the width of the channel is 10-20 μm.

4. The device of claim 1, wherein the device is a composite device for optical storage and electrical storage based on GaSe/InSe heterojunction, and comprises: the metal electrode is at least one of gold, silver, platinum, palladium, chromium and titanium.

5. The device of claim 1, wherein the device is a composite device for optical storage and electrical storage based on GaSe/InSe heterojunction, and comprises: the thickness of the two-dimensional gallium selenide layer is 10-30 nm, and the thickness of the two-dimensional indium selenide layer is 10-20 nm.

6. The device of any of claims 2 to 5, wherein the device is a GaSe/InSe heterojunction-based optical storage and electrical storage composite device, and comprises: the metal is prepared by vacuum evaporation or magnetron sputtering coating, and is contacted with a two-dimensional material by direct deposition or dry transfer, and the two-dimensional material is prepared by mechanically stripping a corresponding material, namely a monocrystalline bulk material, a vapor deposition method or a molecular beam epitaxy method.

7. A method for preparing a GaSe/InSe heterojunction-based optical storage and electrical storage composite device as claimed in any one of claims 1 to 6, wherein the method comprises the following steps: the method comprises the following steps:

step 1, respectively loading the obtained two-dimensional gallium selenide and two-dimensional indium selenide nanosheets on a carrier, and selecting the nanosheets with proper thickness through an optical microscope;

step 2, transferring the two-dimensional gallium selenide nanosheets loaded on the carrier to a silicon substrate with a 300nm oxide layer through a transfer method, and then transferring the two-dimensional indium selenide nanosheets to a two-dimensional gallium selenide layer to obtain a GaSe/InSe heterojunction;

and 3, covering the GaSe/InSe heterojunction channel region in the step 2 by using a mask, and preparing a metal electrode by adopting a vacuum evaporation technology.

8. The method for preparing a composite device of optical storage and electrical storage based on GaSe/InSe heterojunction as claimed in claim 7, wherein: in the step 1, loading the two-dimensional material obtained by a mechanical stripping method on the surface of polydimethylsiloxane in a sticking mode; for a two-dimensional material obtained by vapor deposition or epitaxial growth, a growth substrate is etched after a polymethyl methacrylate film is spin-coated, so that the two-dimensional material is loaded on the surface of PMMA.

9. The method for preparing a composite device of optical storage and electrical storage based on GaSe/InSe heterojunction as claimed in claim 7, wherein: in step 2, the transfer method is a dry transfer method or a wet transfer method.

10. The method for preparing a composite device of optical storage and electrical storage based on GaSe/InSe heterojunction as claimed in claim 7, wherein: in step 3, the mask is a hard mask or a photoresist mask.

Technical Field

The invention belongs to the field of electronics and photoelectrons, and particularly relates to a GaSe/InSe heterojunction-based optical storage and electric storage composite device and a preparation method thereof.

Background

Two-dimensional materials exhibit novel physicochemical properties due to unique structural characteristics, and are widely used in the fields of electronics and optoelectronics. In addition, because the surface of the two-dimensional material has no dangling bond, different two-dimensional materials can be stacked to form a van der Waals heterostructure, and the functionality of the two-dimensional nano material is further widened by utilizing charge transfer and energy band arrangement at an interface.

Hitherto, in the field of electrical storage, one has been able to insert a layer of h-BN, HfO in a heterojunction₂Graphene as a floating gate (Nature Nanotechnology 2021,16: 882-. In the field of optical storage, people build MoS₂A/cPVP/AuNPs device (Advanced Materials 2016,28: 9196-; also, people have constructed MoS₂the/SWCNTs device (Small 2019,15:1804661) utilizes the inherent defects of the carbon nano tube to realize storage, but the device has the defect of instability. In the field of negative light guide, h-BN is introduced as a floating grid to construct MoS₂/BN/ReS₂The device (ACS Nano 2018,12:9513-9520), but the device also has the problems of relatively complex interface and material abrasion in the programming and erasing processes; also, some people have constructed MoS by using defects_2xSe_2(1-x)Devices (Nature Communications 2019,10:4133), but also have the disadvantage of instability. Furthermore, they cannot simultaneously have the functions of electrical storage, optical storage and negative light guide, which greatly limits their applications.

Disclosure of Invention

The invention provides a light storage and electricity storage composite device based on a GaSe/InSe heterojunction and a preparation method thereof, aiming at the problems that the performance of the existing storage device is unstable and can not be simultaneously provided with electricity storage and light storage. The composite memory device realizes the function integration of optical storage and electric storage on the same device by adjusting the energy band arrangement and charge transfer at the heterojunction interface, and provides a novel composite functional device.

In order to achieve the purpose, the technical scheme adopted by the invention is as follows:

a composite device of optical storage and electric storage based on GaSe/InSe heterojunction is shown in figures 1 and 2, and comprises two metal electrodes, two-dimensional indium selenide, two-dimensional gallium selenide and a grid dielectric layer; the device is respectively provided with a grid dielectric layer, a two-dimensional gallium selenide layer and a two-dimensional indium selenide layer from bottom to top, two metal electrodes are arranged on the two-dimensional indium selenide layer and are in contact with the two metal electrodes, a channel is arranged between the metal electrodes, and the width of the channel is 5-30 mu m.

Further, the gate dielectric layer is made of SiO₂、HfO₂、Al₂O₃Sapphire, preferably SiO₂The grid dielectric can apply a vertical electric field to the surface layer material and regulate and control the carrier concentration of the material.

Further, the width of the channel is 10-20 μm, preferably 15 μm.

Further, the metal electrode is at least one of gold, silver, platinum, palladium, chromium, and titanium, and is preferably gold.

Further, the thickness of the two-dimensional gallium selenide layer is 10-30 nm, and preferably 20 nm; the thickness of the two-dimensional indium selenide layer is 10-20 nm, and preferably 16 nm.

Further, the metal is prepared by vacuum evaporation or magnetron sputtering coating and is in contact with the two-dimensional material in a direct deposition or dry transfer mode, and preferably, the metal is directly deposited on the surface of the two-dimensional material by vacuum evaporation; the two-dimensional material is prepared by mechanically stripping a corresponding material monocrystalline bulk material, a vapor deposition method or a molecular beam epitaxy method; preferably, the two-dimensional material is obtained by mechanically peeling a single crystal bulk material.

A preparation method of the optical storage and electric storage composite device based on the GaSe/InSe heterojunction comprises the following steps:

step 1, respectively loading the obtained two-dimensional gallium selenide and two-dimensional indium selenide nanosheets on a carrier, and selecting the nanosheets with proper thickness through an optical microscope;

step 2, transferring the two-dimensional gallium selenide nanosheets loaded on the carrier to a silicon Substrate (SiO) with a 300nm oxide layer through a transfer method₂/Si), transferring the two-dimensional indium selenide nanosheets to a two-dimensional gallium selenide layer to obtain a GaSe/InSe heterojunction;

and 3, covering the GaSe/InSe heterojunction channel region in the step 2 by using a mask, and preparing metal electrodes (namely source and drain electrodes) by adopting a vacuum evaporation technology.

Further, in the step 1, the two-dimensional material obtained by the mechanical stripping method is loaded on the surface of Polydimethylsiloxane (PDMS) in a sticking mode; for a two-dimensional material obtained by vapor deposition or epitaxial growth, a growth substrate is etched after a polymethyl methacrylate (PMMA) film is spin-coated, so that the two-dimensional material is loaded on the surface of PMMA. The carrier is preferably Polydimethylsiloxane (PDMS).

Further, in step 2, the transfer method is a dry transfer method or a wet transfer method, and preferably, the dry transfer method is dry transfer.

Further, in step 3, the mask is a hard mask or a photoresist mask, preferably a hard mask.

Compared with the existing two-dimensional memory device, the invention has the following remarkable effects:

(1) the GaSe/InSe heterojunction device constructed by regulating and controlling the energy band arrangement and the charge transfer at the interface has excellent electrical storage property, V_bg-maxWhen the voltage is 60V, the width of the hysteresis window can reach (Δ V)72.53V, and the storable charge amount (Δ Q) is 5.21 × 10¹²cm^-2On-off ratio of 10 when 2000s is reached³In addition, the device has a simple structure and strong controllability, and is superior to other two-dimensional electric storage devices.

(2) The GaSe/InSe heterojunction device constructed by regulating and controlling the energy band arrangement and the charge transfer at the interface has excellent optical storage property and the on-off ratio of 10⁴After 2000s, the current is only decreased by 6.89nA, and different pulse bias voltages are applied to it to regulate optical power density and optical cycle numberThe optical storage state is effectively regulated and controlled, and the method is superior to other two-dimensional optical storage devices.

(3) The GaSe/InSe heterojunction device constructed by regulating and controlling the energy band arrangement and the charge transfer at the interface has excellent negative photoconductive property, stable performance and the on/off ratio of 10⁴Is superior to other two-dimensional negative optical devices.

(4) The GaSe/InSe heterojunction device constructed by regulating and controlling the energy band arrangement and the charge transfer at the interface is a multifunctional device integrating current storage, light storage and negative light guide, has the storage characteristics of permanent photocurrent and negative light guide, simplifies the structure of the device, realizes the integration of functional devices, greatly widens the application field of the device, and lays a foundation for the application of storage devices in the future.

Drawings

FIG. 1 is a schematic view of a device structure prepared by a GaSe/InSe heterojunction in example 1;

FIG. 2 is a photomicrograph of the GaSe/InSe device of example 1;

FIG. 3 shows different V of GaSe/InSe device corresponding to FIG. 2_bg-maxLower transfer profile;

FIG. 4 is a graph of memory endurance for the corresponding GaSe/InSe device of FIG. 2;

FIG. 5 is a diagram of the optical storage performance of the GaSe/InSe device of FIG. 2 in the high-resistance state when excited by a 532nm light source at room temperature;

FIG. 6 is a graph of the optical storage performance of the GaSe/InSe device 100K of FIG. 2 in a low resistance state under excitation of a 532nm light source;

FIG. 7 is a graph of the transfer curves for the GaSe/BN/InSe device of example 2;

FIG. 8 is a graph of memory endurance for the corresponding GaSe/BN// InSe device of FIG. 7;

FIG. 9 is a graph of the optical storage performance of the GaSe/BN// InSe device of FIG. 7 in the high-resistance state when excited by a 532nm light source at normal temperature.

Detailed Description

The technical solutions of the present invention are further described below with reference to the drawings and the embodiments, but the present invention is not limited thereto, and modifications or equivalent substitutions may be made to the technical solutions of the present invention without departing from the spirit and scope of the technical solutions of the present invention.

The GaSe/InSe heterojunction device constructed by adjusting the energy band arrangement and the charge transfer at the heterojunction interface has the advantages of simple structure, no phenomenon of material abrasion, stronger adjustable capability, high on/off ratio and stable performance, can effectively make up the defects of the existing device, and can realize a multifunctional device integrating current storage, optical storage and negative light guide.

Example 1:

a GaSe/InSe heterojunction device with electric storage, optical storage and negative light guide at the same time comprises the following steps:

firstly, preparing a GaSe layer by a mechanical stripping method, wherein the mechanical stripping method comprises the following specific steps: a PDMS (polydimethylsiloxane) film was attached to the designated end of the slide. And (3) sticking a part of sample from the bulk GaSe by using an adhesive tape, repeatedly folding the adhesive tape in half to gradually reduce the thickness of the sample, and lightly pressing the adhesive tape fully stuck with the target material on the surface of the PDMS film adhered to the glass slide. Pressing for a certain time, slightly uncovering the adhesive tape, placing the adhesive tape on a displacement table of an optical microscope, finding a GaSe nanosheet with the thickness of 10-30 nm, the length of 70-80 mu m and the width of 40-50 mu m by adjusting the position of the displacement table, and transferring GaSe to cleaned SiO by dry transfer₂SiO on/Si substrate₂One side is reserved;

secondly, preparing an InSe nanosheet layer by a mechanical stripping method, wherein the mechanical stripping method comprises the following specific steps: a PDMS (polydimethylsiloxane) film was attached to the designated end of the slide. And (3) sticking a part of sample from the bulk InSe by using an adhesive tape, repeatedly folding the adhesive tape in half to gradually thin the thickness of the sample, and lightly pressing the adhesive tape fully stuck with the target material on the surface of the PDMS film adhered to the glass slide. Pressing for a certain time, slightly removing the adhesive tape, placing the adhesive tape on a displacement table of an optical microscope, finding an InSe nanosheet with the thickness of 10-20 nm, the length of 60-70 mu m and the width of 20-30 mu m by adjusting the position of the displacement table, and transferring the InSe to the GaSe layer obtained in the first step by dry transfer to obtain the GaSe/InSe heterojunction.

And thirdly, covering the prepared GaSe/InSe heterojunction with a mixed-mesh copper net (the channel size is 15 microns, and the electrode size is 200 microns multiplied by 200 microns), respectively reserving positions at two ends, constructing a naked window, adhering one end of the copper net to a silicon dioxide substrate sheet by using heat-resistant glue, if the position of the copper net is slightly displaced, slightly moving the heat-resistant glue by using tweezers or a cotton swab to return the position of the heat-resistant glue, and then fixing the other end of the copper net by using the heat-resistant glue. And thermally depositing Cr/Au electrodes as source and drain electrodes by using an evaporation technology, wherein Cr is about 5nm, gold is about 30nm, and removing the copper mesh after evaporation to complete the preparation of the GaSe/InSe heterojunction device.

Example 2:

this example differs from example 1 in that: in order to verify the charge transfer effect between GaSe and InSe, a BN layer is inserted in a GaSe/InSe heterojunction to block the charge transfer between GaSe and InSe, and the method comprises the following steps:

firstly, preparing a GaSe layer by a mechanical stripping method, wherein the mechanical stripping method comprises the following specific steps: a PDMS (polydimethylsiloxane) film was attached to the designated end of the slide. And (3) sticking a part of sample from the block GaSe by using a 3M Sigao adhesive tape, repeatedly folding the adhesive tape in half to gradually reduce the thickness of the sample, and lightly pressing the adhesive tape fully stuck with the target material on the surface of the PDMS film adhered to the glass slide. Pressing for a certain time, slightly uncovering the adhesive tape, placing the adhesive tape on a displacement table of an optical microscope, finding a GaSe nanosheet with the thickness of 20-30 nm, the length of 70-80 mu m and the width of 40-50 mu m by adjusting the position of the displacement table, and transferring GaSe to cleaned SiO by dry transfer₂SiO on/Si substrate₂One side is reserved;

secondly, preparing the BN nano-sheet layer by a mechanical stripping method, wherein the mechanical stripping method comprises the following specific steps: a PDMS (polydimethylsiloxane) film was attached to the designated end of the slide. And (3) sticking a part of sample from the block BN by using a 3M Sigao adhesive tape, repeatedly folding the adhesive tape in half to gradually reduce the thickness of the sample, and lightly pressing the adhesive tape fully stuck with the target material on the surface of the PDMS film adhered to the glass slide. Pressing for a certain time, slightly removing the adhesive tape, placing the adhesive tape on an optical microscope displacement table, finding a BN nanosheet with the thickness of about 10nm, the length of 70-80 microns and the width of 50-60 microns by adjusting the position of the displacement table, and transferring BN to the GaSe layer obtained in the first step by dry transfer to obtain a GaSe/BN heterojunction for later use;

preparing an InSe nanosheet layer by a mechanical stripping method, wherein the mechanical stripping method comprises the following specific steps: a PDMS (polydimethylsiloxane) film was attached to the designated end of the slide. And (3) sticking a part of sample from the block InSe by using a 3M Sigao adhesive tape, repeatedly folding the adhesive tape in half to gradually reduce the thickness of the sample, and lightly pressing the adhesive tape fully stuck with the target material on the surface of the PDMS film adhered to the glass slide. And pressing for a certain time, slightly removing the adhesive tape, placing the adhesive tape on a displacement table of an optical microscope, finding an InSe nanosheet with the thickness of 20-30 nm, the length of 60-70 mu m and the width of 20-30 mu m by adjusting the position of the displacement table, and transferring the InSe to the GaSe/BN heterojunction obtained in the second step by dry transfer to obtain the GaSe/BN/InSe heterojunction.

Fourthly, the prepared GaSe/BN/InSe heterojunction is covered by a mixed-mesh copper net (the channel size is 15 mu m, the electrode size is 200 mu m multiplied by 200 mu m), positions of two ends are respectively reserved, a naked window is constructed, one end of the copper net is firstly glued to a silicon dioxide substrate sheet by using heat-resistant glue, if the position of the copper net is slightly displaced, the heat-resistant glue is slightly moved by using tweezers or a cotton swab to return to the position, and then the other end of the copper net is fixed by using the heat-resistant glue. And thermally depositing Cr/Au electrodes as source and drain electrodes by using an evaporation technology, wherein Cr is about 5nm, gold is about 30nm, and removing the copper mesh after evaporation to complete the preparation of the GaSe/BN/InSe related heterojunction device.

In order to verify the effect of the embodiment, the GaSe/InSe heterojunction and the GaSe/BN/InSe heterojunction obtained in the above embodiments are prepared into devices, and the specific process is as follows:

the invention was verified with the following tests:

test one: the electrical storage property of the GaSe/InSe heterojunction device is detected to obtain the relationship graphs shown in figures 3 and 4,as can be seen from the figure, when V is_bg-maxWhen the voltage is 60V, the width of the hysteresis window can reach (Δ V)72.53V, and the storable charge amount (Δ Q) is 5.21 × 10¹²cm^-2On-off ratio of 10 when 2000s is reached³Indicating that the GaSe/InSe heterojunction device has excellent electrical storage properties.

And (2) test II: the electrical storage properties of the GaSe/BN/InSe heterojunction device are detected to obtain the relationship graphs shown in figures 5 and 6, and the graphs can be seen from V_bg-maxWhen the voltage is 50V, the width (Δ V) of the hysteresis window is 14.12V, and the storable charge amount is 1.01 × 10¹²cm^-2When the switching ratio reaches 500s, the switching ratio is only 10 and is far smaller than that of a GaSe/InSe heterojunction device, and the excellent electric storage property of the GaSe/InSe heterojunction device is related to the energy band arrangement and charge transfer at an interface.

And (3) test III: the photo-storage property of the GaSe/InSe heterojunction device is detected to obtain a relation graph as shown in FIG. 7, and as can be seen from the graph, the GaSe/InSe heterojunction device has a permanent photocurrent phenomenon under the excitation of a high-resistance 532nm light source, and the on-off ratio is 10⁴And after 2000s, the current is only reduced by 6.89nA, which shows that the GaSe/InSe heterojunction device has excellent optical storage property.

And (4) testing: the optical storage property of the GaSe/BN/InSe heterojunction device is detected to obtain a relation graph as shown in figure 8, and as can be seen from the graph, the GaSe/BN/InSe heterojunction device also has a permanent photocurrent phenomenon, the current is only reduced by 0.30nA after 500s, the on-off ratio is less than 10 and is far lower than that of the GaSe/InSe heterojunction device, and the excellent optical storage property of the GaSe/BN/InSe heterojunction device is related to the energy band arrangement and the charge transfer at an interface.

And (5) testing: at 100K, the optical storage property of the GaSe/InSe heterojunction device is detected, a relation graph as shown in FIG. 9 is obtained, and it can be seen from the graph that after a first light pulse is added, the current drops suddenly, a very obvious negative photoconduction phenomenon is realized, and the on/off ratio is 10⁴。