Photoresponse of homostructure WSe2 rectifying diode

Tien-Hsin Peng,Chung-Hung Hong,Ming-Ru Tang,Si-Chen Lee

doi:10.1063/1.5115423

Abstract

The WSe2 homostructure rectifying diode is demonstrated, p-type and n-type WSe2 regions were formed by adopting different layer WSe2 thicknesses. Typically, the common way to fabricate two dimensional material based diode is to use heterostructure by stacking two different carrier type and band gap energies materials. However, there is always lattice mismatch at the junction, leading to the degraded photoresponse of the diodes. In order to reduce the problems of heterostructure diode, layer thickness dependent band gap energy of WSe2 is reported and applied to fabricate homostructure diode. The ideality factor of the current-voltage characteristic is 1.64 and the current rectification ratio can reach to 103. The optical properties of the diode, including fill factor 45.7%, responsivity 16.02 mA/W and EQE 3.06% are reported. It is concluded that the WSe2 homojunction diode can be applied in photodetectors, switches, solar cells etc.

Highlights

It was shown that the band gap of WSe2 would decrease as the thickness become larger.[20] Based on this characteristic, it was found that the electrical performance of the WSe2 TFTs would be different from the thick channel to the thin one
transition-metal dichalcogenide (TMDC) have been widely applied in photodetector because of the strong light-matter interactions and excellent flexibility,[6–11] and have superior immunity to short channel effect due to their ultra-thin body nature and much lower dielectric constants than those of the conventional Si, Ge and III-V com-pound semiconductors.[12]
The material properties would be significantly changed according to the size and charge of both transition metal and chalcogen elements

Summary

Introduction

It was shown that the band gap of WSe2 would decrease as the thickness become larger.[20] Based on this characteristic, it was found that the electrical performance of the WSe2 TFTs would be different from the thick channel to the thin one. The WSe2 flakes was exfoliated and transferred onto the patterned substrate by scitation.org/journal/adv

Results

Conclusion