CN111312849B

CN111312849B - Piezoelectric photoelectronic photoelectric detector and construction method thereof

Info

Publication number: CN111312849B
Application number: CN201910412627.0A
Authority: CN
Inventors: 潘曹峰; 徐迁
Original assignee: Beijing Institute of Nanoenergy and Nanosystems
Current assignee: Beijing Institute of Nanoenergy and Nanosystems
Priority date: 2019-05-17
Filing date: 2019-05-17
Publication date: 2021-09-14
Anticipated expiration: 2039-05-17
Also published as: CN111312849A

Abstract

The invention relates to the technical field of micro-nano energy, and discloses a structure of a piezoelectric photoelectronics photoelectric detector based on a heterojunction, wherein the photoelectric detector comprises: the piezoelectric device comprises a substrate, an adhesion layer, a conductive channel layer, a piezoelectric material layer and two-end electrodes. The adhesion layer is arranged on the substrate 1, the conductive channel layer 3 is arranged on the adhesion layer 2, the piezoelectric material layer 4 is arranged on the conductive channel layer 3, and the two-end electrodes 5 are distributed at the left end and the right end of the conductive channel layer 3 and are not in contact with the piezoelectric material layer 4. In the novel device structure, the current flowing through the device only passes through the semiconductor with high carrier mobility in the device, and the limitation of the structure with the electrodes connected in series with the interface on the performance of the device is eliminated, so that the device has the characteristic of being regulated and controlled by a mechanical input signal and the characteristic of actively detecting the strain.

Description

Piezoelectric photoelectronic photoelectric detector and construction method thereof

Technical Field

The invention relates to the technical field of micro-nano energy sources, in particular to a structure of a multifunctional photoelectric detector with adjustable performance and capable of detecting strain borne by a device.

Background

A photodetector is a basic semiconductor device that utilizes the photoelectric properties of a semiconductor to cause a change in conductivity within the semiconductor through a change in the concentration of photogenerated carriers within the semiconductor, ultimately resulting in a change in the photodetector current. The traditional photoelectric detector simply relies on the photoelectric effect of a semiconductor, and has single function and extremely limited performance. With the continuous development of wearable technology, flexible electronics, internet of things technology and the like, the photoelectric detector with single function cannot meet the development requirements of emerging technology, and the multifunctional integrated photoelectric detector more accords with the development trend in the future.

Piezoelectric optoelectronics is a new research field, and mechanical strain borne by a semiconductor photoelectric device can be used as an input signal to adjust the processes of generation, transportation, separation, compounding and the like of photon-generated carriers through the piezoelectric optoelectronics effect. By utilizing the effect, the mechanical input signal can regulate and control the performance of the photoelectric detector; meanwhile, the change of the performance of the photoelectric detector is used as the reaction to the mechanical input signal, and the active detection to the mechanical input signal can also be realized. Therefore, the novel photoelectric detector with adjustable performance and multifunction integration can be realized by utilizing the piezoelectric photoelectronic effect.

At present, in a device structure of a piezoelectric optoelectronic photodetector, an interface barrier such as a heterojunction or a schottky junction is essential to realize performance regulation. Among them, the piezoelectric optoelectronic photodetector based on the heterojunction is very concerned by researchers due to the advantage of being able to combine different materials. However, in the prior art of such devices, the operation of the device is generally based on passing photogenerated carriers sequentially through the interfaces between the respective materials under the drive of a voltage. In the conventional device design in which the electrode and each material interface are connected in series, if the carrier mobility of one material is not good, the photocurrent of the whole device is severely suppressed, because the advantages of the used materials cannot be effectively combined. Moreover, this inherent design mode of connecting electrodes in series with the material interface has hindered the development of piezoelectric optoelectronic photodetectors, and new device designs can inject new activity for the development of this field.

In various heterojunction photoelectric detectors, a heterojunction device formed by a two-dimensional material and lead-halogen perovskite can combine the high carrier mobility of the two-dimensional material and the excellent photoelectric properties and piezoelectric properties of the lead-halogen perovskite. However, in the prior art of such devices, only polycrystalline thin films of lead-halogen perovskites, quantum dots, or multiple single crystals with disordered orientation are typically employed. Therefore, the introduction of the piezoelectric property of the lead-halogen perovskite into the device becomes a difficult point, and the realization of the piezoelectric photoelectron photoelectric detector based on the binary semiconductor and the lead-halogen perovskite heterojunction also becomes a challenge which is difficult to complete.

Disclosure of Invention

(1) Technical scheme

The invention provides a novel device structure of a heterojunction piezoelectric photoelectron photoelectric detector, and breaks through the design of devices in which electrodes are connected with interfaces of various materials in series in the devices. In this design, include: a substrate; the heterojunction is built on the substrate and is composed of two materials, wherein one material is a semiconductor material with high mobility as a conductive channel layer, the other material has obvious piezoelectric property and has light absorption performance and photoelectric effect superior to those of the conductive channel layer, the two materials are vertically stacked on the substrate to form the heterojunction, and the two materials for assembling the heterojunction are tightly combined to ensure that an effective photon-generated carrier transport process exists at the interface of the heterojunction; electrodes are formed at both ends of the high mobility semiconductor material, and the electrodes are in contact with only the high mobility semiconductor material.

It is often difficult to have both high carrier mobility and excellent photovoltaic and light absorption properties in one material, and the design provided by the present invention can effectively combine the above-mentioned advantages in different materials.

In the structure provided by the invention, the high-mobility semiconductor material is used as a unique conductive channel layer, and compared with a device structure in which an electrode and each material interface are connected in series, the device design provided by the invention is more favorable for realizing large photocurrent under the same photon-generated carrier concentration; in addition, a single conductive channel layer also facilitates suppression of dark current. The interface of the heterojunction can have the transportation of a photon-generated carrier, so that the introduction of a material with stronger light absorption and excellent photoelectric property is beneficial to increasing the concentration of the photon-generated carrier in the conductive channel layer and helping the conductive channel layer to overcome the performance limitation caused by poor light absorption or photoelectric effect; finally, the coupling of the piezoelectric effect, the semiconductor property and the optical excitation in the device generates the piezoelectric photoelectronic effect, so that the device shows the characteristics that the performance can be regulated by a mechanical input signal and the strain on the active detection.

In order to realize the structural design of the device, the invention provides a piezoelectric photoelectronic photodetector based on a two-dimensional semiconductor and a lead-halogen perovskite heterojunction, which comprises a substrate, a first electrode, a second electrode, a third electrode and a fourth electrode, wherein the substrate is provided with a first electrode and a second electrode; the piezoelectric device comprises a substrate, a conductive channel layer, a piezoelectric material layer and two end electrodes. The conductive channel layer is positioned on the substrate, the piezoelectric material layer is positioned on the conductive channel layer, and the electrodes are positioned on the substrate, distributed at the left end and the right end of the piezoelectric material layer and not in contact with the piezoelectric material layer.

Further, the photoelectric property of the piezoelectric material layer is superior to that of the conductive channel layer;

and/or, under the same conditions, the piezoelectric material layer generates more photogenerated carriers than the conductive channel layer.

Furthermore, the conducting channel layer is a two-dimensional nano material thin layer and a one-dimensional nano thin layer; preferably, the thin layer material is WS₂。

Further, the piezoelectric material layer is wurtzite or perovskite material;

preferably, the piezoelectric material layer is a single crystal micron/nanowire or micron/nanorod of a lead-halogen perovskite material;

more preferably, the single-crystal micron/nanowire of the lead-halogen perovskite material is single CsPbBr₃Single crystal microwire.

Further, the substrate is a hard or flexible substrate;

preferably, the substrate is PEN or Si/SiO₂。

Further, the conductive channel layer is in contact with the two end electrodes, and the electrode material is Cr/Au;

preferably, the thickness of the electrode material Cr at the two ends is 5-20 nm, and the thickness of Au is 20-50 nm.

Furthermore, the size of the conductive channel layer is that the thickness is less than 15nm, the width is more than 200nm, and the length is more than 1.5 μm.

Furthermore, the piezoelectric material layer is single CsPbBr₃A single crystal microwire;

preferably, the micrometer wire has a diameter ranging from 400nm to 1 μm and a length greater than 20 μm.

Further, the substrate comprises an adhesion layer, and the conductive channel layer is located on the adhesion layer.

Furthermore, the adhesion layer is made of silicon dioxide or a high polymer material.

(2) Advantageous effects

Firstly, the piezoelectric photoelectron photoelectric detector gets rid of an inherent structure formed by connecting electrodes and interfaces of various materials in series through the novel structure of the piezoelectric photoelectron photoelectric detector provided by the invention; secondly, the structure of the high-mobility semiconductor material as the only conductive channel layer overcomes the defect that the whole performance of the device is suppressed even if the mobility of only one material is poor in the structure of the electrode and each material interface in series connection, so that the improvement of photocurrent is facilitated, and the single channel layer also brings convenience for dark current suppression, thereby improving the performance of the device; thirdly, the advantages of different materials in the heterojunction are complemented and combined more effectively through the device structure; finally, the piezoelectric property of the lead-halogen perovskite is firstly applied to a piezoelectric photoelectron photoelectric detector based on a heterojunction, the proposed device structure provides a new idea for the structural design of the piezoelectric photoelectron photoelectric detector, and the research range of the device is expanded. The proposed device structure can realize a high-performance, performance-tunable, and multifunctional photodetector (i.e., device performance varies with strain while actively sensing strain).

Drawings

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:

FIG. 1A is a schematic cross-sectional structure of a heterojunction piezoelectric optoelectronic photodetector of the present invention;

FIG. 1B is a schematic top view of a heterojunction piezoelectric optoelectronic photodetector of the present invention;

FIG. 1C is a schematic device structure of a heterojunction piezoelectric optoelectronic photodetector of the present invention;

FIG. 2 is a flow chart of a method;

FIG. 3A photograph of a fixed point transfer device

FIG. 3B transfer sticker photo

FIG. 3C is a schematic cross-sectional view of the transfer sticker

WS for constructing heterojunction in the first embodiment of FIG. 4A₂Nano thin layer and CsPbBr₃Single crystal micron line

FIG. 4B photomicrograph of the first embodiment after the heterojunction has been assembled

FIG. 4C shows a heterojunction piezoelectric optoelectronic photodetector constructed as described in the first embodiment

FIG. 4D Electron micrograph of heterojunction piezoelectric optoelectronics photodetector of the first embodiment

Photo of a PEN substrate with a device built in the second embodiment of FIG. 5A

FIG. 5B is a schematic diagram of an apparatus for stressing a device of the example

FIG. 5C is a schematic diagram of an apparatus and method for applying tensile strain to a device in an example

FIG. 5D schematic drawing of an apparatus and method for applying tensile strain to a device in an example

Heterojunction constructed as in the second embodiment of figure 6A

FIG. 6B is a schematic diagram of a device under tensile strain in a second embodiment

FIG. 6C is a schematic representation of a device under compressive strain in a second embodiment

FIG. 7A second example Current-Voltage curves for devices under different strains

FIG. 7B second example dark current for device under different strains

FIG. 7C second example device photocurrent and responsivity at different strains

FIG. 7D second example device photocurrent at different strains versus photocurrent at no strain

FIG. 7E Effect of Positive piezoelectric Charge introduced into the heterojunction interface on the device band Structure

Figure 7F impact of negative piezoelectric charge introduced into the heterojunction interface on the device band structure.

Description of the reference numerals

1, a substrate; 2, an adhesion layer; 3a conductive channel layer; 4a layer of piezoelectric material; 5 two-terminal electrodes; 6a transparent glass slide with a transfer sticker; 7, transparent double-sided adhesive tape; 8 thicker PDMS films; 9, transparent single-sided adhesive; 10 another layer of transparent double-sided adhesive tape; 11 thin PDMS film; 12PPC layer.

Detailed Description

The following detailed description of embodiments of the invention refers to the accompanying drawings. It should be understood that the detailed description and specific examples, while indicating the present invention, are given by way of illustration and explanation only, not limitation.

Firstly, the novel device structure of the piezoelectric photoelectron photoelectric detector based on the heterojunction provided by the invention is explained.

FIG. 1 is a schematic diagram of a heterojunction piezoelectric optoelectronic photodetector according to an embodiment of the present invention. Fig. 1A is a schematic structural view of a cross section of the structure, and fig. 1B is a schematic structural view of a top view of the structure.

As shown in fig. 1, an embodiment of the present invention provides a heterojunction piezoelectric optoelectronic photodetector including: a substrate 1; an adhesion layer 2 formed on the substrate 1, the adhesion layer 2 not being required when a material for constructing a heterojunction can be firmly adsorbed on the substrate 1; the conductive channel layer 3 is positioned on the adhesion layer 2, and is positioned on the substrate 1 when the adhesion layer 2 does not exist; a layer of piezoelectric material 4, having photoelectric properties superior to those of said conductive channel layer 3, on said conductive channel layer 3; and two end electrodes 5 formed on the conductive channel layer 3, distributed at both left and right ends of the conductive channel layer, and prevented from contacting the piezoelectric material layer 4. More photogenerated carriers can be generated under the same conditions.

In the heterojunction piezoelectric photoelectron photoelectric detector of the invention, the photoelectric property of the piezoelectric material layer 4 is superior to that of the conductive channel layer 3. The conductive channel layer 3 is made of a semiconductor channel material with high mobility, and the piezoelectric material layer 4 generates more photon-generated carriers than the conductive channel layer 3 under the same condition.

Through the technical scheme, the piezoelectric photoelectron optical detector with a novel structure based on the heterojunction can be realized, and the novel structure is obviously different from a structure that electrodes and various material interfaces are connected in series, which is common in the prior similar device technology. Since the electrodes at both ends are only in contact with the semiconductor channel layer with high mobility, only the semiconductor channel layer with high mobility itself plays a role in conduction. The structure avoids the series connection structure, thereby avoiding the pressing of the material with poor mobility in the heterojunction on the photocurrent of the device and improving the performance of the device. The semiconductor with high mobility does not always have light absorption, photoelectric property and piezoelectric property which are superior to those of other materials, but in the novel structure, the defect of mobility can be ignored, and a material with better light absorption, photoelectric property and piezoelectric property can be selected, and the material and the semiconductor with high mobility are stacked to form a heterojunction, so that the advantages of the two materials can be combined, the defects of the two materials can be overcome, and the performance of the piezoelectric photoelectron photoelectric detector can be further improved.

According to one embodiment of the invention: the substrate 1 is a rigid or flexible substrate. The adhesion layer 2 is not necessarily present, and the adhesion layer 2 is necessarily present if the bonding force between the material for constructing the heterojunction and the substrate is not sufficient to adhere the material to the substrate, and the adhesion layer 2 is preferably a silicon dioxide layer or a high molecular polymer layer formed on the substrate 1. The conductive channel layer 3 is a low-dimensional nanomaterial with high carrier mobility, and may be a two-dimensional nanomaterial thin layer or a one-dimensional nanoribbon with high carrier mobility. The piezoelectric material layer 4 should have better light absorption than the conductive channel layer 3 and good photoelectric effect, and may be wurtzite, perovskite material, preferably single crystal micron/nanowire, micron/nanorod of lead-halogen perovskite material. In order to provide good contact between the conductive channel layer 3 and the piezoelectric material layer 4, the surfaces of the two that are in contact with each other should have good flatness and cleanliness.

According to one embodiment of the present invention, the thickness of the conductive channel layer 3 may range from less than 100 nm; the diameter of the piezoelectric material layer 4 may range less than 1 μm; the thickness of the two-terminal electrode 5 may be in a range of 30nm to 60 nm.

FIG. 1C is a three-dimensional schematic diagram of a device structure according to an embodiment of the invention, comprising a substrate 1; an adhesion layer 2; a conductive channel layer 3; a piezoelectric material layer 4; two-terminal electrode 5

FIG. 2 is a flow chart of a method of constructing a heterojunction piezoelectric optoelectronic photodetector according to one embodiment of the present invention.

As shown in fig. 2, the method includes: preparing a substrate, transferring a conductive channel layer material to the substrate, accurately transferring a piezoelectric material layer to the surface of the conductive channel layer material by a fixed-point transfer method to form a heterojunction, and forming two-end electrodes at two ends of the conductive channel layer by using electron beam lithography and electron beam evaporation methods.

The following is a specific example using the preferred conditions in FIG. 1C (except that the substrate used in this example is Si/SiO₂The hard substrate, and other constraints are the same as the preferred conditions described above in connection with FIG. 1C. And the replacement of the substrate does not have any influence on the following steps), this example constructs a heterojunction piezoelectric optoelectronic photodetector, and the following is a corresponding method:

first, a mechanical lift-off method was used to prepare the two-dimensional WS₂Placing the nano thin layer on the surface of the substrate; then using fixed point transfer method to transfer CsPbBr₃Single crystal micron line to two-dimensional WS₂Forming a heterojunction on the surface of the nano thin layer; two-dimensional WS using electron beam lithography and electron beam evaporation₂Two end electrodes are formed on the surface of the nano thin layer.

To achieve the above steps, the present invention next provides a method for constructing a heterojunction by site-directed transfer under the above preferred conditions.

Fig. 3A is a photograph of a fixed-point transfer device, which mainly includes an optical microscope, a three-dimensional displacement stage, and a vacuum adsorption stage having heating and cooling functions.

In addition to the transfer device, a transfer sticker as shown in fig. 3B is required, the transfer sticker is fixed at one end of a slide glass, and the slide glass is required to be fixed on the three-dimensional displacement table during use.

Fig. 3C is a schematic cross-sectional structure of the transfer patch. As shown in fig. 3C, a transfer sticker is fixed on the slide 6, and the transfer sticker structure includes: a transparent double-sided adhesive tape 7; a PDMS membrane 8, preferably 2mm thick, preferably 4mm long and wide; a transparent single-sided tape 9, which is wound on the glass slide 6 to tighten the PDMS film 8 into a shape with an arc-shaped upper surface; a transparent double-sided tape 10 attached to the surface of the transparent single-sided tape 9; a PDMS film 11, preferably 500 μm thick and 4mm long and wide, attached to the arc-shaped surface of the transparent double-sided adhesive tape 10; and a PPC film 12 formed on the surface of the PDMS film 11. The preparation method of the PPC thin film is to spin-coat a PPC solution (preferably, anisole is used as a solvent, the preferred concentration is 15% by mass, and the preferred rotation speed is 1500rpm) on the surface of the PDMS thin film 11, and then dry (preferably, 90 ℃, 10min), that is, form the PPC thin film 12 on the surface of the PDMS thin film 11. When the transfer sticker is assembled, the prepared PDMS/PPC film is cut into a proper size after the steps are completed, and the PDMS/PPC film is attached to the surface of the transparent double-sided adhesive tape 10.

The slide with the transfer sticker is fixed on a three-dimensional displacement table in fig. 3A by fixing one end of the slide away from the transfer sticker at a position shown by an arrow in fig. 3A by using a single-sided adhesive tape, the fixed slide is in a horizontal position, and a PPC layer in the transfer sticker is downward.

FIG. 4A shows WS used in constructing a heterojunction in this embodiment₂Nano thin layer and CsPbBr₃Single crystal microwire. When constructing the heterojunction, a fixed-point transfer device is used for transferring the center of the paste and the CsPbBr₃Aligning the single crystal micron line, and vertically descending the transfer paste by using a three-dimensional displacement platform until the single crystal micron line is aligned with the CsPbBr₃Contacting the monocrystal micrometer line, raising the temperature of the vacuum adsorption platform, maintaining for 5min at 60 deg.C, cooling the sample and the transfer patch by lowering the temperature of the vacuum adsorption platform (preferably 40 deg.C), and lifting the cooled transfer patch with a three-dimensional displacement table, wherein CsPbBr is added₃The single crystal microwire is separated from the growth substrate and fixed on the transfer paste to be prepared with the WS₂Placing a substrate of a nano-thin layer below the transfer paste, and adjusting the WS by using a fixed-point transfer device₂The position and orientation of the nano-thin layer is such that WS₂Nanoflayers and CsPbBr₃The relative positions of the single crystal microwires are shown in fig. 4B.

Fig. 4B is a photomicrograph after the heterojunction has been assembled. Adjusting the WS according to the above steps₂Nanoflayers and CsPbBr₃After the relative position of the single crystal micron line, the CsPbBr is adhered by a three-dimensional displacement table₃The transfer paste of the single crystal micron line is vertically lowered until the WS₂Nanoflayers and CsPbBr₃Contacting the single crystal micrometer lines, raising the temperature of the vacuum adsorption platform, keeping the temperature for a period of time (preferably 60 ℃, keeping the temperature for 15min), slowly and vertically lifting the transfer paste by using a three-dimensional displacement platform under the condition of keeping the temperature unchanged, wherein the PPC layer in the transfer paste is connected with the CsPbBr₃The single crystal micron line is left in the WS₂The nano thin layer is arranged on the substrate. After the PPC is dissolved using a solvent, preferably dichloromethane, the heterojunction in fig. 4B is obtained.

FIG. 4C shows a completed heterojunction piezoelectric photoelectron photodetector, and it should be noted that CsPbBr is added in FIG. 4C₃The electrodes where the single crystal microwires are perpendicular to each other and attempted to be connected are not part of the device design of the present invention, and the two electrodes do not play any role in this example and the present invention, and the two electrodes are only attempted for other experimental effects and do not have any influence on the present invention.

FIG. 4D is an electron micrograph of the heterojunction piezoelectric photoelectron photodetector clearly showing that the device structure of this example is consistent with the device structure provided by the present invention, in which the two end electrodes are only connected with the conducting channel layer WS₂In contact with a nano-thin layer and CsPbBr₃There are significant gaps between the single crystal microwires.

Next, another embodiment provided according to the embodiments of the present invention shows stress (strain) regulation characteristics and active probing characteristics for strain of the constructed device. The present example applies the same preferred conditions as the above example except that the substrate is a flexible substrate. In this example, the flexible substrate is preferably a PEN substrate, cut to size and shape (preferably circular, 2cm in diameter) before use. In addition to the steps involving the substrate, the present example builderThe method of the device is also identical to the previous embodiment. To enable PEN to adhere to CsPbBr₃The single crystal micron line has one magnetically controlled sputtered silica adhering layer formed on the surface of PEN substrate before use.

Fig. 5A is a photograph of a PEN substrate with a device built.

Fig. 5B is a schematic diagram of an apparatus for stressing the device of this example. Fig. 5C and 5D are schematic diagrams of an apparatus and method for applying tensile and compressive strain, respectively, to the device of this example.

Fig. 6A is a photograph of a heterojunction (not a device, an electrode structure of the device following the design in the present invention) constructed in the present example.

Fig. 6B and 6C are schematic diagrams of the device in this example when subjected to tensile and compressive strain, respectively.

Fig. 7A is a current-voltage curve for a device under different strains, showing the significant effect of strain on device performance over the range tested. Furthermore, due to WS₂Nano thin layer and CsPbBr₃Single crystal microwires are preferred materials with appropriate matching of the energy bands to WS₂A depletion layer is generated in the nano-thin layer, and thus dark current of the device is low.

FIG. 7B shows dark current at different strains, and it can be seen that even at higher strains, the applied strain has little effect on the dark current of the device, not enough to break WS₂Depletion state of the nanolayer.

Fig. 7C shows photocurrent and responsivity at different strains. FIG. 7D is a plot of the ratio of photocurrent at different strains to that without strain, showing that the maximum photocurrent, divided by the applied strain, yields 11.3 times the modulation (calculated as photocurrent at 0.11% divided by photocurrent at-0.11%).

Fig. 7E illustrates the effect of positive piezoelectric charge introduced at the heterojunction interface on the device band structure. As shown in FIG. 7E, when positive piezoelectric charge is introduced at the heterojunction interface, the positive charge causes CsPbBr₃Is shifted up, and at this time CsPbBr₃And WS₂Which still maintains a thermal equilibrium, resulting in a steeper bending of the energy band at the interface than when no positive charge is introduced. In addition, due to the shadow of the depletion layerSound, positive piezoelectric charge pair WS₂Also generates a certain electric field regulation, thereby leading WS at the interface to be₂The energy bands produced weak downward bending, but according to the test results (fig. 7B), the bending was not sufficient to break WS₂Is depleted. Therefore, the bending of the energy band at the interface is shown by the thick dashed line in fig. 7E, compared to when no positive charge is introduced (shown by the shallow thin line).

Fig. 7F is a graph of the effect of negative piezoelectric charge introduced at the heterojunction interface on the device band structure. The band at the heterojunction interface produces the change shown by the thick dashed line in fig. 7F based on the same principle that causes the band structure change in fig. 7E.

In this example, CsPbBr₃The single crystal microwire has excellent light absorption and photoelectric properties, so CsPbBr₃Photon-generated carriers in the single-crystal microwire are transferred to WS via the heterojunction interface₂This process of nano-thin layer has a significant impact on the performance of the device. The band change in fig. 7E obstructs this carrier transfer process and thus the photocurrent is reduced; the band change in fig. 7F is more favorable to help the photogenerated carriers overcome the potential barrier encountered during transfer and thus the photocurrent of the device increases.

Claims

1. A piezoelectric optoelectronic photodetector, comprising,

a substrate;

a conductive channel layer on the substrate, the conductive channel layer being a two-dimensional nanomaterial thin layer or a one-dimensional nanoribbon thin layer made of WS₂；

The piezoelectric material layer is positioned on the conductive channel layer and is made of wurtzite or perovskite materials;

and the two-end electrodes are positioned on the substrate, distributed at the left end and the right end of the conductive channel layer and are not in contact with the piezoelectric material layer.

2. A piezoelectric optoelectronic photodetector as claimed in claim 1, wherein said layer of piezoelectric material has superior optoelectronic properties to said conductive channel layer;

3. A piezoelectric optoelectronic photodetector as claimed in claim 1, wherein the layer of piezoelectric material is a single crystal micro/nanowire, micro/nanorod of lead-haloperovskite-type material.

4. A piezoelectric optoelectronic photodetector as claimed in claim 3, wherein the single crystal microwire/nanowire of lead-halo perovskite-like material is a single CsPbBr₃Single crystal microwire.

5. A piezoelectric optoelectronic photodetector as claimed in claim 1, wherein said substrate is a rigid or flexible substrate.

6. A piezoelectric optoelectronic photodetector as claimed in claim 5, wherein said substrate is PEN or Si/SiO₂。

7. A piezoelectric optoelectronic photodetector as claimed in claim 1 wherein said conductive channel layer is in contact with said end electrodes, the electrode material being Cr/Au.

8. A piezoelectric optoelectronics photodetector according to claim 7, wherein the thickness of the electrode material Cr of the both-end electrodes is 5 to 20nm, and the thickness of Au is 20 to 50 nm.

9. A piezoelectric optoelectronic photodetector as claimed in claim 1 wherein said conductive channel layer is dimensioned to be less than 15nm thick, greater than 200nm wide and greater than 1.5 μm long.

10. A piezoelectric optoelectronic photodetector as claimed in claim 4, wherein said microwire has a diameter in the range of 400nm to 1 μm and a length greater than 20 μm.

11. A piezoelectric optoelectronic photodetector as claimed in claim 1 wherein said substrate comprises an adhesion layer, said conductive channel layer being on said adhesion layer.

12. A piezoelectric optoelectronic photodetector as claimed in claim 11, wherein the material of the adhesion layer is silica or a polymeric material.