Optical Transition between Metal and Semiconductor in Graphene and MoS2
일 시 : 2021년 06월 02일 수요일 16:00
연 사 : 임 성 주 교수 (성균관대학교 에너지학과)
장 소 : 자연과학관 747호 & 온라인 진행 ( https://us02web.zoom.us/j/89101846374, 회의 ID: 891 0184 6374)
HOST : 김 은 규 교수님
초 록
Graphene is a semimetal with zero bandgap, and MoS2 is a semiconductor with a bandgap larger than 1.0 eV. Optical characterizations of these materials reveal that depending on the carrier concentration, they show optical characteristics representing either the metal or the semiconductor. For instance, both materials exhibit the photoconductive effect under the incident light at low carrier concentration, resulting from an increase of excess carriers in the conduction band. However, photoconductive behavior switches to photothermal one at high carrier concentration, contributing to the decrease of photoconductance by excess carriers. The switchable optical behavior of MoS2 is harnessed to develop a photodetector capable of detecting from the visible to the mid-IR range.