Journal Article

Repairing atomic vacancies in single-layer MoSe2 field-effect transistor and its defect dynamics

Wang, Baigeng, Wang, Peng, Wang, Guanghou, Wang, Xinran, Song, You, Bu, Haijun, Gao, Si, Ling, Chongyi, Meng, Yuze, Wang, Xuefeng, Song, Fengqi, Wang, Jinlan, Xin, Run

2017

Overview

Atomic defects are easily created in the single-layer electronic devices of current interest and cause even more severe influence than in the bulk devices since the electronic quantum paths are obviously suppressed in the two-dimensional transport. Here we find a drop of chemical solution can repair the defects in the single-layer MoSe 2 field-effect transistors. The devices’ room-temperature electronic mobility increases from 0.1 cm 2 /Vs to around 30 cm 2 /Vs and hole mobility over 10 cm 2 /Vs after the solution processing. The defect dynamics is interpreted by the combined study of the first-principles calculations, aberration-corrected transmission electron microscopy, and Raman spectroscopy. Rich single/double Selenium vacancies are identified by the high-resolution microscopy, which cause some mid-gap impurity states and localize the device carriers. They are found to be repaired by the processing with the result of extended electronic states. Such a picture is confirmed by a 1.5 cm −1 red shift in the Raman spectra. Two-dimensional materials: Repairing atomic defects via solution processing Defects can heavily influence the electrical transport properties of three-dimensional materials. But their impact becomes even more pronounced in low-dimensional systems. Fengqi Song and colleagues use a combination of calculations and experiments to show that a simple drop of a chemical solution can repair the selenium vacancies in field-effect transistors made from single layer molybdenum diselenide. By reducing the number of vacancies, which localize the electronic transport, the authors increased the carrier mobilities to nearly the intrinsic value by 2–3 orders of magnitude. The defect dynamics is visualized by the high resolution electron microscopy and multislice simulations. Such an approach could provide a route for enabling practical devices to be made from these relatively fragile materials.

• Publisher: Nature Publishing Group UK,Nature Publishing Group,Nature Portfolio
• Subject: 639/301/1005/1007 / 639/301/357/995 / Condensed Matter Physics / Defects / Doppler effect / Electron states / Electron transport / Electronic devices / Field effect transistors / First principles / High resolution / High resolution electron microscopy / Hole mobility / Mathematical analysis / Microscopy / Molybdenum compounds / Physics / Physics and Astronomy / Quantum Physics / Raman spectra / Raman spectroscopy / Red shift / Repair / Room temperature / Selenium / Semiconductor devices / Spectrum analysis / Structural Materials / Surfaces and Interfaces / Thin Films / Transistors / Transport properties / Two dimensional materials / Vacancies