Photoelectric Characteristics of Isotype Heterostructure p-WSe2/p-Si Photodetector with Improved Photoresponsivity and Detectivity

A heterojunction photodetector was fabricated for thefirst timevia chemical vapor deposition by combining a p-type WSe2 monolayered triangular flake with a p-type Si substrate. Under illumination,the p-p isotype heterojunction exhibited a broad photoresponserange of 400-1550 nm under LED and laser light. The introductionof monotriangular and atomic thick p-WSe2 flakes onto p-typeSi greatly increased the photodetection capability with a long carrierlifetime and robust light absorption. The best performance of thisdevice exhibited a minimized dark current of 5 nA, a record high photocurrent-to-dark-currentratio of & SIM;28111.88, an ultrahigh detectivity of 2.075 x10(15) jones, a high external quantum efficiency (EQE) of133132%, and a high responsivity of 568.6 A/W under light illuminationof 532 nm with 9.17 mW/cm(2) intensity. These engrossingresults indicate that this p-WSe2/p-Si heterojunction devicehas considerable potential for applications in next-generation photodetectors.