Optimizing Light Sensing Capabilities of WSe2 FETs through Chemical Modulation of Carrier Dynamics

Two-dimensional semiconductor materials demonstrate interesting electronic and optoelectronic properties, which can be further modulated through chemical doping to control carrier concentration and enhance device performance. This study explores the doping process of a few-layer thin WSe2 using FeCl3 solution as a dopant. We perform a thorough characterization utilizing Raman analysis and electrical testing to validate the doping of WSe2. The investigations reveal the p-type doping effect and a notable rise in hole concentration, further elucidated via the energy band diagram. Additionally, the WSe2 field-effect transistor (FET) operation is investigated under illumination with light of different wavelengths ranging from 220 nm to 514 nm both before and after doping. Following p-type doping, the device exhibited a notable increase in current, indicative of improved performance in photodetection. The responsivity and external quantum efficiency (EQE) are improved significantly after doping. This research confirms the effectiveness of p-type doping in WSe2 and highlights its impact in enhancing the electronic and optoelectronic characteristics of WSe2 devices. The results underscore the potential for advancing electronic and optoelectronic applications through such enhancements. [Display omitted] •Tailored Electronic Structure: Explore the intentional modification of tungsten diselenide (WSe2) electronic structure through p-type doping, employing Iron (III)-chloride (FeCl3) dopant solutions with a concentration of 5 mM.•Polarity Shifts: Presenting the impact of doping via electrical behavior, with transfer curves displaying a distinctive shift like charge carrier's nature, establishing the effectiveness of chemical doping in few-layer thin WSe2 field-effect transistors on SiO2/Si substrates.•Enhanced Photoresponse: Investigate the implications of p-type doping on the photoresponse of the WSe2 device, demonstrating a significant increase in responsivity and external quantum efficiency (EQE). This enhancement suggests improved performance in photodetection applications.•Advanced Applications: The research validates the successful p-type doping of 2D materials, emphasizing its potential for optimizing the electrical and optoelectronic properties of TMDC-based devices. These insights position WSe2 as a promising material for advanced applications in electronic and optoelectronic technologies.