Significantly enhanced optoelectronic performance of tungsten diselenide phototransistor via surface functionalization
- 341 Downloads
Two-dimensional (2D) layered transition metal dichalcogenides (TMDs) have attracted enormous research interests and efforts towards the development of versatile electronic and optical devices, owing to their extraordinary and unique fundamental properties and remarkable prospects in nanoelectronic applications. Among the TMDs, tungsten diselenide (WSe2) exhibits tunable ambipolar transport characteristics and superior optical properties such as high quantum efficiency. Herein, we demonstrate significant enhancement in the device performance of WSe2 phototransistor by in situ surface functionalization with cesium carbonate (Cs2CO3). WSe2 was found to be strongly doped with electrons after Cs2CO3 modification. The electron mobility of WSe2 increased by almost one order of magnitude after surface functionalization with 1.6-nm-thick Cs2CO3 decoration. Furthermore, the photocurrent of the WSe2-based phototransistor increased by nearly three orders of magnitude with the deposition of 1.6-nm-thick Cs2CO3. Characterizations by in situ photoelectron spectroscopy techniques confirmed the significant surface charge transfer occurring at the Cs2CO3/WSe2 interface. Our findings coupled with the tunable nature of the surface transfer doping method establish WSe2 as a promising candidate for future 2D materialsbased optoelectronic devices.
KeywordsWSe2 in situ surface transfer doping performance enhancement phototransistor cesium carbonate
Unable to display preview. Download preview PDF.
W. C. acknowledges the financial support from Singapore MOE Grant R143-000-652-112, National Natural Science Foundation of China (No. 21573156) and the technical support from Centre for Advanced 2D Materials and Graphene Research Centre for the device fabrication. G. E. acknowledges Singapore National Research Foundation, Prime Minister’s Office, Singapore, for funding the research under its Medium-sized Centre program as well as NRF Research Fellowship (No. NRF-NRFF2011-02). G. E. also acknowledges financial support from Singapore MOE (No. MOE2015-T2-2-123).