Charge noise in low Schottky barrier multilayer tellurium field-effect transistors

Abstract

Creating van der Waals (vdW) homojunction devices requires materials with narrow bandgaps and high carrier mobilities for bipolar transport, which are crucial for constructing fundamental building blocks like diodes and transistors in a 2D architecture. Following the recent discovery of elemental 2D tellurium, here, we systematically investigate the electrical transport and flicker noise of hydrothermally grown multilayer tellurium field effect transistors. While the devices exhibit a dominant p-type behavior with high hole mobilities up to ∼242 cm² V⁻¹ s⁻¹ at room temperature and almost linear current–voltage characteristics down to 77 K, ambipolar behavior was observed in some cases. Through a detailed temperature dependent transport characterization, we estimated the Schottky barrier height as low as ∼20 meV. The good electrical contacts further facilitate the observation of metal-to-insulator transition at low temperature, being an intrinsic property of the tellurium channel rather than the contacts. Finally, detailed low frequency noise spectroscopy shows dominant 1/f type behavior across the entire gate-voltage range. The origin of the observed noise can be described by Hooge's mobility fluctuation model, rather than the carrier number fluctuations due to interfacial traps. We anticipate that such analysis will contribute to the development of futuristic low-noise devices using tellurium.