Preparation method of flexible photoelectric detector based on selenide/sulfide heterojunction

Abstract

The invention discloses a flexible photoelectric detector based on a selenide/sulfide heterojunction and a preparation method thereof. The sensor adopts a PI film as a substrate, ITO as an electrode, and a heterojunction formed by a P-type selenide with a forbidden band width of 1.2-2.4 eV (such as GaSe with a forbidden band width of about 2.1 eV) and an n-type sulfide with a forbidden band width of 1.8-2.2 eV (such as MoS2 with a forbidden band width of about 1.8 eV) as a functional layer. The preparation method of the flexible photoelectric detector comprises the following steps: firstly, acquiring an ITO electrode through a photoetching technology and ITO wet etching, then acquiring a submicron slice of selenide and sulfide by adopting a mechanical stripping mode, accurately aligning the submicron slice with the ITO electrode, and transferring the submicron slice to the ITO electrode based on a PI substrate to form an ultrathin two-dimensional semiconductor heterojunction (wherein the thickness of each layer is in a range of 10 nm to 30 nm) with an area of a junction region being in a range of 1*10<2> to 2.5*10<3> square microns. The preparation method is convenient, environment-friendly and cheap; the selenide/sulfide heterojunction photoelectric detector prepared based on the method has good bendability, can be applied to more scenes compared with a rigid photoelectric detector, and can be applied to more fields due to the material characteristics of the selenide/sulfide heterojunction; and the photoelectric detector has good photoelectric detection performance and can achieve good photoelectric detection effect.

Description

technical field [0001] The invention belongs to the field of photoelectric sensors and relates to the preparation of a flexible photodetector based on a selenide / sulfide heterojunction. Background technique [0002] With its outstanding performance in fields such as healthcare monitoring and energy harvesting, flexible electronics has attracted widespread attention. It uses a soft substrate instead of the traditional rigid substrate, which can be better shaped and adapted to different substrates, and can still maintain good performance under bending, stretching, etc., and can be used on the surface of the skin, etc., to realize wearable electronic devices , providing a large number of new functions for some practical applications. One of the major trends in the development of wearable devices is the use of flexible photoelectric sensors. High-performance optical detectors play an important role in many fields, and their applications include electro-optical display, photose...

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Problems solved by technology

[0004] However, most of the current methods for preparing heterojunctions based on mechanical exfoliation use rigid substrates, which cannot be flexible. Ordinary flexible substrates will react with acetone during the removal of photoresist and destroy the device. Therefore, it is necessary to find an insoluble substrate. flexible substrate in acetone

In addition, when using flexible substrates for electrode preparation, most of the substrates need to be fixed on rigid substrates. Currently, there is a method of fixing by spin-coating pmma solution, but this method is expensive and pmma is toxic. Therefore, it is necessary to find a new method. way to fix

[0005] At present, most photodetectors use metal as electrodes, but due to the doping effect of metal electrodes on two-dimensional semiconductors, the trap states in two-dimensional semiconductors, and the Fermi level pinning effect, metal electrodes are easily combined with two-dimensional semiconductors. The material forms a Schottky contact, thereby inhibiting the photoelectric performance of the selenide / sulfide heterojunction. Therefore, in order to improve the photodetection performance, it is necessary to find a new electrode material to replace the common metal electrode material.

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