Negative infrared photocurrent response in layered WS2/reduced graphene oxide hybrids

TitleNegative infrared photocurrent response in layered WS2/reduced graphene oxide hybrids
Publication TypeJournal Article
Year of Publication2014
AuthorsRatha, S, Simbeck, AJ, Late, DJ, Nayak, SK, Rout, CSekhar
JournalApplied Physics Letters
Volume105
Issue24
Pagination243502
Date PublishedDEC
ISSN0003-6951
Abstract

We report high performance IR photocurrent response of two-dimensional hybrid materials consisting of layered WS2 nanosheets and reduced graphene oxide (RGO). Comparative photocurrent response studies of WS2 nanosheets, RGO, and WS2/RGO hybrids were carried out by performing current-voltage (I-V) and time-dependent current measurements with a laser excitation source having a wavelength of 808 nm. The experimental investigations indicate that WS2/RGO hybrids show negative photocurrent response, whereas WS2 and RGO show positive photocurrent response. The negative photocurrent response of the WS2/RGO hybrids is explained using a band alignment diagram and attributed to a charge transfer mechanism between WS2 and RGO. This analysis is further corroborated by first-principles density functional calculations. The fabricated device based on WS2/RGO hybrids shows a photosensitivity R-lambda of about 6 AW(-1) and a quantum efficiency eta of similar to 924%, which demonstrates high sensitivity of the hybrid material towards IR detection. WS2/RGO hybrids are therefore promising candidates for potential applications in optoelectronic circuits and low cost, high performance, and reliable photodetectors. (C) 2014 AIP Publishing LLC.

DOI10.1063/1.4903780
Type of Journal (Indian or Foreign)Foreign
Impact Factor (IF)3.48
Divison category: 
Physical and Materials Chemistry