Enhanced Photocurrent in MoS₂-based Field-Effect Transistors Driven by two indices of Laguerre-Gaussian Light

YeRu Chen^1*, Kristan Bryan Simbulan², GuanHao Peng³, YuChen Chang¹, ShunJen Cheng³, TingHua Lu¹, YannWan Lan¹

¹Department of Physics, National Taiwan Normal University, Taipei, Taiwan
²Department of Mathematics and Physics, University of Santo Tomas, Manila, Philippines
³Department of Electrophysics, National Yang Ming Chiao Tung University, Hsinchu, Taiwan

* Presenter:YeRu Chen, email:81141005S@gapps.ntnu.edu.tw

This study explores the impact of Laguerre-Gaussian (LG) light, characterized by azimuthal (l) and radial (p) indices, on the photoresponse of a MoS₂ Field-Effect Transistor (FET). LG light’s unique profile creates a donut-shaped intensity distribution from the azimuthal index, which introduces quantized orbital angular momentum (OAM), while the radial index generates a ripple-like structure across the radial plane. By directing a linearly polarized 532 nm laser onto a spatial light modulator (SLM), we produce the LG phase distribution and employ it as an excitation source for the MoS₂ FET. Experimental results demonstrate a notable increase in photocurrent with higher radial indices and further enhancements when coupling both azimuthal and radial indices, underscoring the synergistic effect on the MoS₂ FET’s photoresponse. This enhancement in free carrier concentration may be attributed to an increased exciton dissociation rate facilitated by LG light. The multi-level photocurrent improvement demonstrated in this study suggests substantial potential for LG-driven optoelectronic applications in MoS₂-based devices, paving the way for advanced, tunable light-based device architectures.

Keywords: Laguerre Gaussian beam, MoS2 FET, orbital angular momentum, radial index of LG beam