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.