Photodetector based on heterostructure of two-dimensional WSe₂/In₂Se₃

Abstract

Heterojunctions formed by two-dimensional (2D) layered semiconducting materials have been studied extensively in the past few years. These van der Waals (vdW) structures have shown great potential for future electronic and optoelectronic devices. However, the optoelectronic performance of these devices is limited by the indirect band gap of multilayer materials and low light absorption of single layer materials. Here, we fabricate photodetectors based on heterojunctions composed of n-type multilayer α-indium selenide (In2Se3) and p-type tungsten diselenide (WSe2) for the first time. The direct band gap of multilayer α-In2Se3 and type-II band alignment of the WSe2/In2Se3 heterojunction enable high optoelectronic performance of the devices at room temperature in the air. Without light illumination, the dark current is effectively suppressed to 10−13 A under −1 V bias and a high rectification ratio of 7.37 × 103 is observed. Upon laser illumination with a wavelength of 650 nm, the typical heterojunction device exhibits a photocurrent on/off ratio exceeding 1.24 × 105, a maximum photo responsivity of 26 mA W−1 and a short photoresponse time of 2.22 ms. Moreover, the heterojunction photodetectors show obvious light response in the wavelength range from 650 nm to 900 nm. The present 2D vdW heterojunctions composed of direct band gap multilayer materials show great potential for future optoelectronic devices.

Photosensitive activity of fabricated core-shell composite nanostructured p-CuO@CuS/n-Si diode for photodetection applications

“…As the core/shell combinations of TMO and TMC are expected to enhance the photocurrent and responsivity of the photo detector. Most of the core/shell heterojunction-based photodiodes was reported on p-type or n-type material, still efficiency in Photo response is lagging, to achieve better photo response both material for the heterojunction employed as p-type semiconducting material [ 30 ].…”

Piezo‐Phototronic Effect in 2D α‐In2Se3/WSe2 van der Waals Heterostructure for Photodetector with Enhanced Photoresponse

“…Based on the difference in the bandgap and work function between α‐In 2 Se 3 and WSe 2 , the predictable type‐II band alignment was formed in the vdW heterojunction, while the experimental results further show the property similar to that from diodes. [ 33 ] Figure a displays the offset occurred between the valence band and conduction band of n‐type α‐In 2 Se 3 /p‐type WSe 2 heterojunction without light illumination, external strain, and voltage bias. Therefore, the built‐in electric field is induced at the interface.…”

2D van der Waals Heterojunction Nanophotonic Devices: From Fabrication to Performance

“…Photodetectors are optoelectronic devices that generate charge separation by absorbing light whose photon energy is greater than the energy of semiconductor bandgap and converting the light into an electrical signal. [78,79] In recent years, 2D vdWhs have been used to fabricate photodetectors with high response and detection speeds.…”

“…[66] Copyright 2019, Elsevier Ltd. large dark current and slow response time on the order of milliseconds or even seconds are possible. [78,79] Heterojunctions can solve this problem, but for a traditional heterojunction, we need to dope the homogeneous materials or perform epitaxial growth on lattice-matched substrate materials. Therefore, to form excellent heterojunctions, it is important to match the lattice constants of the two materials.…”