Hybrid quantum dot-tin disulfide field-effect transistors with improved photocurrent and spectral responsivity

• Published in: Applied physics letters 2016-03, Vol.108 (12)
• Main Authors: Huang, Yuan, Zang, Huidong, Nam, Chang-Yong, Chen, Jia-Shiang, Cotlet, Mircea, Department of Materials Science and Engineering, Stony Brook University, Stony Brook, New York 11794, Sutter, Eli A., Sutter, Peter W.
• Format: Article
• Language: English
• Subjects: CADMIUM SELENIDES; CARRIER DENSITY; CARRIER MOBILITY; CHARGE CARRIERS; CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; DISULFIDES; FIELD EFFECT TRANSISTORS; PHOTOCURRENTS; PHOTOLUMINESCENCE; PHOTOSENSITIVITY; QUANTUM DOTS; TIN SULFIDES; WAVELENGTHS; ZINC SULFIDES
• ISSN: 0003-6951; 1077-3118

We report an improved photosensitivity in few-layer tin disulfide (SnS{sub 2}) field-effect transistors (FETs) following doping with CdSe/ZnS core/shell quantum dots (QDs). The hybrid QD-SnS{sub 2} FET devices achieve more than 500% increase in the photocurrent response compared with the starting SnS{sub 2}-only FET device and a spectral responsivity reaching over 650 A/W at 400 nm wavelength. The negligible electrical conductance in a control QD-only FET device suggests that the energy transfer between QDs and SnS{sub 2} is the main mechanism responsible for the sensitization effect, which is consistent with the strong spectral overlap between QD photoluminescence and SnS{sub 2} optical absorption as well as the large nominal donor-acceptor interspacing between QD core and SnS{sub 2}. We also find enhanced charge carrier mobility in hybrid QD-SnS{sub 2} FETs which we attribute to a reduced contact Schottky barrier width due to an elevated background charge carrier density.