Photoelectric detector of two-dimensional material based on interface modification

Abstract

The utility model discloses a photoelectric detector of a two-dimensional material based on interface modification. The photoelectric detector comprises a substrate, an oxide layer, a channel layer, a metal electrode and an interface modification layer. The preparation process of the device comprises the following steps: preparing the SiO2 oxide layer, the WSe2 channel layer, the metal electrode and the Pentacene interface modification layer on the P-type heavily doped Si substrate in sequence to obtain the photoelectric detector. A Pentacene organic material is evaporated on a WSe2 two-dimensional semiconductor, the thickness of the WSe2 is 1-80 nanometers, the thickness of the Pentacene is 10-30 nanometers, a metal electrode is gold, silver or copper, and the thickness of the metal electrode is 20-100 nanometers. Compared with the prior art, the device has the advantages that the Pentacene is adopted to modify the WSe2 channel layer, and a plurality of photo-generated excitons generated in the Pentacene film migrate to the WSe2 and are decomposed into electrons and hole carriers to move to the two ends of the electrode under the illumination condition, so that the light current is increased, the light responsivity of the device in red light and near-infrared light regions is enhanced, and the photoelectric conversion efficiency of the device is improved. Therefore, the photoelectric detector can be used for a wide-spectrum near-infrared photoelectric detector.

Description

Technical Field

[0001] The utility model relates to the field of preparation of optoelectronic devices, in particular to a photoelectric detector based on interface-modified two-dimensional materials. Background Art

[0002] Two-dimensional (2D) materials offer tremendous possibilities for next-generation optoelectronic devices due to their excellent optical and electronic properties and specific physicochemical characteristics. The absorption bands of these layered materials cover a wide range of the electromagnetic spectrum and exhibit strong interactions between light and materials, making them suitable for a wide range of optoelectronic applications.

[0003] Multilayer WSe2 can provide a wider NIR spectral band due to its narrow bandgap characteristics. WSe2 has been used in semiconductor devices to achieve lightness and flexibility on any surface. Since WSe2 has no dangling bonds and does not need to consider lattice matching issues, it can form heterojunctions with other materials through the action of van der Waals forces, so the application range of WSe2 has become more and more extensive. Pentacene is a P-type organic semiconductor material with a multi-benzene ring structure, high hole mobility, and good absorption at a wavelength of 650nm. It can be grown on WSe2 by vacuum evaporation without any undesirable electronic deformation. Detectors based on the photoconductivity effect have been widely studied due to their simple preparation process, but such devices usually have slow response speeds and low switching ratios, which limits their application range. The mixed structure of WSe2 and Pentacene can enhance the light detection performance of multilayer WSe2. Summary of the invention

[0004] In order to further improve the performance of the WSe2 photodetector, the utility model provides a WSe2 photodetector based on interface modification. The photodetector comprises, from bottom to top, a substrate 1, an oxide layer 2, a channel layer 3, a metal electrode 4, and an interface modification layer 5 that completely covers the WSe2 film 3 and partially covers the metal electrode 4.

[0005] Furthermore, the substrate 1 is a P-type heavily doped Si substrate;

[0006] Further, the oxide layer 2 is SiO2, and the thickness is 300±15 nanometers;

[0007] Furthermore, the channel layer 3 is a WSe2 thin film with a thickness of 1-80 nanometers;

[0008] Furthermore, the metal electrode 4 is any material of gold, silver or copper, and has a thickness of 10-100 nanometers;

[0009] Furthermore, the interface modification layer 5 is Pentacene, and has a thickness of 10-30 nanometers;

[0010] The utility model has the following beneficial effects:

[0011] The utility model deposits a layer of Pentacene as a modification layer on the WSe2 two-dimensional semiconductor, and cleverly combines the inorganic two-dimensional material with the organic photosensitive material to form a new type of heterostructure, which can greatly improve the photosensitivity of the device and broaden the absorption spectrum. In addition, the device structure with buried electrodes increases the area of ​​the Pentacene on the top of the device that receives light and increases the number of carriers. The photodetector prepared according to the utility model broadens the absorption spectrum, and the light response and specific detection rate are also improved compared with the simple WSe2 photodetector. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 A structural diagram of a photoelectric detector based on interface-modified two-dimensional materials provided by the utility model;

[0013] Figure 1 Description of labels:

[0014] 1-Si substrate

[0015] 2-SiO2 oxide layer

[0016] 3-WSe2 channel layer

[0017] 4-Metal Electrode

[0018] 5-Pentacene interface modification layer

[0019] Figure 2 The AFM images and thickness of WSe2 in the embodiment (above) and the comparative example (below) of the present invention are shown;

[0020] Figure 3 The (red) photocurrent I of the embodiment and comparative example devices of the utility model under 650nm laser with different optical powers ph ; (blue) light responsivity R; DETAILED DESCRIPTION

[0021] In order to make the content of the utility model clearer and easier to understand, the utility model is described in detail below in conjunction with the accompanying drawings and the following embodiments:

[0022] Example:

[0023] Substrate preparation: A SiO2 oxide layer with a thickness of about 300 nm was prepared on a clean P-type heavily doped Si substrate by thermal oxidation.

[0024] Two-dimensional material transfer: Through the mechanical peeling method, the WSe2 crystal is pasted to the blue glue and transferred with a PDMS film. The PDMS film is covered on the blue glue with WSe2, torn off and then covered on the substrate. Heat and slowly tear off to remove the PDMS film to complete the transfer of WSe2.

[0025] Preparation of metal electrodes: Use photolithography or electron beam exposure to evaporate gold, silver or copper onto the wafer using thermal evaporation.

[0026] Preparation of interface modification layer: Use a mask to properly cover the metal electrode area of ​​the device, and then evaporate Pentacene onto WSe2 by thermal evaporation, thus obtaining a photodetector based on interface-modified two-dimensional materials.

[0027] Comparative Example:

[0028] Substrate preparation: A SiO2 oxide layer with a thickness of about 300 nm was prepared on a clean P-type heavily doped Si substrate by thermal oxidation.

[0029] Two-dimensional material transfer: Through the mechanical peeling method, the WSe2 crystal is pasted to the blue glue and transferred with a PDMS film. The PDMS film is covered on the blue glue with WSe2, torn off and then covered on the substrate. Heat and slowly tear off to remove the PDMS film to complete the transfer of WSe2.

[0030] Preparation of metal electrodes: Use photolithography or electron beam exposure to evaporate gold, silver or copper onto the wafer using thermal evaporation. Thus, a field effect transistor based on WSe2 is prepared.

[0031] The preferred specific embodiments of the present invention are described in detail above, and some photoelectric tests are compared with the comparative examples. Figure 3 As shown, it further demonstrates the effect of introducing the Pentacene interface modification layer on improving device performance.

[0032] It should be understood that ordinary technology in the field can make many modifications and changes based on the concept of the utility model without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art based on the concept of the utility model through logical analysis, reasoning or limited experiments on the basis of the existing technology should be within the scope of protection determined by the claims.

Claims

1. A photodetector based on interface-modified two-dimensional materials, the photodetector comprising, from bottom to top, a Si substrate, a SiO2 oxide layer, a WSe2 channel layer, a metal electrode, and a Pentacene interface modification layer, characterized in that: The photodetector device based on interface-modified two-dimensional materials uses two-dimensional material WSe2 as a channel material and uses organic material Pentacene as an interface modification layer. The thickness of the two-dimensional material WSe2 is 1-80nm, the thickness of the metal electrode is 10-100nm, and the thickness of Pentacene is 10-30nm.

2. A photoelectric detector based on interface-modified two-dimensional materials according to claim 1, characterized in that: The two-dimensional material WSe2 is transferred to the SiO2 oxide layer by a mechanical exfoliation transfer method.

3. The photoelectric detector based on interface-modified two-dimensional materials according to claim 1, characterized in that: The Pentacene interface modification layer is prepared by thermal evaporation.

4. The photoelectric detector based on interface-modified two-dimensional materials according to claim 1, characterized in that: The metal electrode is made of any one of gold, silver or copper.

5. The photoelectric detector based on interface-modified two-dimensional materials according to claim 1, characterized in that: The substrate is P-type heavily doped silicon, and the thickness of the SiO2 oxide layer is 300±15nm.

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