High-responsivity broadband photodetection of an ultra-thin In2S3/CIGS heterojunction on steel

Cu(In, Ga)Se-2 (CIGS) is a promising light harvesting material for large-area broadband photodetection, but it has been rarely studied up to now. Here an In2S3/CIGS heterojunction photodiode on steel is shown to be highly broadband photo-sensitive, with a photoresponsivity over 0.8 A/W, an external quantum efficiency over 100%, and a detectivity over 8 x 10(10) Jones from 505 to 910nm under a reverse bias of 1 V. Moreover, the CIGS photodiode exhibits an outstanding weak light detection ability (i.e., at light power density of 20 mu W/cm(2)), reaching a record. responsivity of 2.06 A/W, an impressive EQE of 293%, and a good detectivity of 2.3 x 10(11) Jones at 870 nm under 1 V reverse bias. Importantly, the CIGS photodiode, working as a self-powered photodetector, under 0 V, shows a record. detectivity of similar to 3.4 x 10(12) Jones with a high responsivity of similar to 0.44 A/W and a high EQE of similar to 63%, at 870 nm. (C) 2021 Optical Society of America

Automated summary

This study demonstrates a highly broadband photo-sensitive In2S3/CIGS heterojunction photodiode with excellent photoresponsivity and detectivity. Additionally, the CIGS photodiode shows outstanding performance under weak light conditions as well.