Ultrafast photoresponse in n-MoS2/AlN/p-Si (SIS) heterojunction based visible to NIR photodetectors

Abstract

In the present study, n-MoS2/p-Si and n-MoS2/AlN/p-Si Semiconductor-Insulator-Semiconductor (SIS) heterojunctions based photodetectors have been fabricated using dc magnetron sputtering technique. The recorded value of responsivities for both n-MoS2/p-Si and n-MoS2/AlN/p-Si heterojunctions are found to be 0.3378 AW-1 and 1.865 AW-1 for visible radiations (532 nm) and 0.1245 AW-1 and 1.4743 AW-1 for NIR radiations (1064 nm), respectively. The response time (rise time and decay time) of the fabricated heterojunction decreased from 47.30 μs and 56.58 μs to 3.32 μs and 4.73 μs with the insertion of an ultrathin insulating AlN layer. The higher current flows in SIS heterojunction can be ascribed to the carrier tunneling mechanism through the ultrathin insulating layer. Moreover, the thickness effect of the insulating layer on the photodetection performance of the fabricated heterostructure has been investigated. The obtained results demonstrate that SIS heterojunctions with an excellent carrier transport mechanism are proved to be potential candidates in next-generation ultrafast optoelectronics applications.