The Effect of Dielectric Capping on Few-Layer Phosphorene Transistors: Tuning the Schottky Barrier Heights

Han Liu, Purdue University, Birck Nanotechnology Center
Adam T. Neal, Purdue University, Birck Nanotechnology Center
Mengwei Si, Purdue University, Birck Nanotechnolgy Center
Yuchen Du, Purdue University, Birck Nanotechnology Center
Peide D. Ye, Birck Nanotechnology Center and School of Electrical and Computer Engineering, Purdue University

Abstract

Phosphorene is a unique single elemental semiconductor with two-dimensional layered structures. In this letter, we study the transistor behavior on mechanically exfoliated few-layer phosphorene with the top-gate. We achieve a high ON-current of 144 mA/mm and hole mobility of 95.6 cm(2)/V.s.. We deposit Al2O3 by atomic layer deposition (ALD) and study the effects of dielectric capping. We observe that the polarity of the transistors alternated from p-type to ambipolar with Al2O3 grown on the top. We attribute this transition to the changes for the effective Schottky barrier heights for both electrons and holes at the metal contact edges, which is originated from fixed charges in the ALD dielectric.

Discipline(s)

Nanoscience and Nanotechnology