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Updated: Apr 16, 2026
All-electronic Nanosecond-resolved Scanning Tunneling Microscopy: Facilitating the Investigation of Single Dopant Charge Dynamics
Published on: January 19, 2018
Trap density probing on top-gate MoS₂ nanosheet field-effect transistors by photo-excited charge collection
Kyunghee Choi1, Syed Raza Ali Raza, Hee Sung Lee
1Institute of Physics and Applied Physics, Yonsei University, 50 Yonsei-ro, Seodaemun-gu, Seoul 120-749, Korea. semicon@yonsei.ac.kr.
Abstract:
Two-dimensional (2D) molybdenum disulfide (MoS₂) field-effect transistors (FETs) have been extensively studied, but most of the FETs with gate insulators have displayed negative threshold voltage values, which indicates the presence of interfacial traps both shallow and deep in energy level. Despite such interface trap issues, reports on trap densities in MoS₂ are quite limited. Here, we probed top-gate MoS₂ FETs with two- (2L), three- (3L), and four-layer (4L) MoS₂/dielectric interfaces to quantify deep-level interface trap densities by photo-excited charge collection spectroscopy (PECCS), and reported the result that deep-level trap densities over 10(12) cm(-2) may exist in the interface and bulk MoS₂ near the interface. Transfer curve hysteresis and PECCS measurements show that shallow traps and deep traps are not that different in density order from each other. We conclude that our PECCS analysis distinguishably provides valuable information on deep level interface/bulk trap densities in 2D-based FETs.
