Anisotropic interface characteristics of bilayer GeSe based field effect transistors

Abstract

Moderate direct band gap and strong stability render bilayer gemanium selenide (GeSe) more suitable for the channel material in the electronic and optoelectronic devices. To improve carrier injection efficiency in an actual two dimensional device, the choice of the metal electrode is a key issue. Here using both electronic band calculations and quantum transport simulation, we comprehensively investigate the interface characteristics of bilayer GeSe contacted with six representative metals. The projected band structures of bilayer GeSe on these metals illustrate that all of these bilayer GeSe have undergone metallization, resulting in the contact natures are ohmic in the vertical interface. While，anisotropic lateral Schottky contacts are formed between the Ag, Au, Pd, Pt, Cu and bilayer GeSe along the armchair and the zigzag direction. The Ni electrode forms p-type quasi-Ohmic contact with bilayer GeSe with a small hole Schottky barrier height of 0.04 (0.08) eV along the armchair (zigzag) direction. Thus, the high performance of bilayer GeSe based FET would be realized by choosing the Ni as source/drain electrodes.