title: Bipolar Junction Transistors in Two-Dimensional WSe2 with Large Current and Photocurrent Gains.
abstract: In the development of semiconductor devices, the bipolar junction transistor (BJT) features prominently as being the first solid state transistor that helped to usher in the digital revolution. For any new semiconductor, therefore, the fabrication and characterization of the BJT are important for both technological importance and historical significance. Here, we demonstrate a BJT device in exfoliated TMD semiconductor WSe2. We use buried gates to electrostatically create doped regions with back-to-back p-n junctions. We demonstrate two central characteristics of a bipolar device: current gain when operated as a BJT and a photocurrent gain when operated as a phototransistor. We demonstrate a current gain of 1000 and photocurrent gain of 40 and describe features that enhance these properties due to the doping technique that we employ.
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY-Polytechnic Institute , Albany, New York 12203, United States.
authors.forename: Pratik
authors.initials: P
authors.lastname: Agnihotri
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY-Polytechnic Institute , Albany, New York 12203, United States.
authors.forename: Prathamesh
authors.initials: P
authors.lastname: Dhakras
authors.affiliation: Colleges of Nanoscale Science and Engineering, SUNY-Polytechnic Institute , Albany, New York 12203, United States.
authors.forename: Ji Ung
authors.initials: JU
authors.lastname: Lee
keywords: Bipolar junction transistor; current gain; photocurrent gain; transition metal dichalcogenides; two-dimensional semiconductors