The effect of DUV-O2 doping on WSe2 FET for sensing applications: Experimental and theoretical approach

Abstract

Tungsten Diselenide (WSe2) is an emerging electronic material among the TMDCs family exhibiting unique properties, like high surface-to-volume ratio with direct bandgap. Although the external factors contribute majorly on system’s outcome, but the environmental problems can be resolved to achieve the high efficiency of device. Here, to resolve the environmental factors and to improve the efficiency of WSe2 based field effect transistors (FETs), p-type doping effect from (deep ultraviolet light) DUV ​+ ​O2 (oxygen) treatment using mechanical exfoliation method has been employed. By the p-type doping through DUV ​+ ​O2 treatment, the mobility, the ION/IOFF ratio and the charge carrier density enhanced to 68 ​cm2/V, 0.46 ​× ​107 and 4.6 ​× ​1012 ​cm−2 respectively. This doping effect is further confirmed by the negative change of threshold voltage (Vth) as well as Raman peaks at higher wavelength values. Moreover, the structural, optical, and electronic properties of pristine and doped WSe2 by first principal calculations were also investigated. For these theoretical calculations, the full-potential linearized augmented plane wave (FP-LAPW) with Heyd-Scuseria-Ernzerhof hybrid functional (HSE) and generalized gradient approximation (GGA) approach has been utilized to the Quantum espresso and WIEN2k code respectively. For the optical analysis and to examine the behavior of the material before and after doping in the band structure the substitution of oxygen in chalcogenides Se was studied.