Direct Observation of Band Gap Renormalization in Layered Indium Selenide.

Zhang, Zailan; Chen, Zhesheng; Bouaziz, Meryem; Giorgetti, Christine; Yi, Hemian; Avila, Jose; Tian, Bingbing; Shukla, Abhay et al. · ACS Nano · 2019

basic_science · Level V

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Abstract

Manipulation of intrinsic electronic structures by electron or hole doping in a controlled manner in van der Waals layered materials is the key to control their electrical and optical properties. Two-dimensional indium selenide (InSe) semiconductor has attracted attention due to its direct band gap and ultrahigh mobility as a promising material for optoelectronic devices. In this work, we manipulate the electronic structure of InSe by <i>in situ</i> surface electron doping and obtain a significant band gap renormalization of ∼120 meV directly observed by high-resolution angle resolved photoemission spectroscopy. This moderate doping level (carrier concentration of 8.1 × 10<sup>12</sup> cm<sup>-2</sup>) can be achieved by electrical gating in field effect transistors, demonstrating the potential to design of broad spectral response devices.