High-Performance Nano-Schottky Diodes and Nano-MESFETs Made on Single CdS Nanobelts

摘要

Nano-Schottky diodes and nanometal-semiconductor field-effect transistors (MESFETs) on single CdS nanobelts (NBs) have been fabricated and studied. The Au/CdS NB Schottky diodes have very low reverse current density (~3.0×10<'-5> A·cm<'-2> at -10V reverse bias) and the highest on/off current ratio (~10<'8>) reported so far for nano-Schottky diodes. The single CdS NB MESFETs exhiblt n- channel normally on (depletion) mode, low threshold voltage (~-1.55 V), high transconductance (~3.5μS), low subthreshold swing (~ 45mV/dec), and the highest on/off current ratio (~2×10<'6>) reported so far for nanofield-effect transistors. We also show that the absolute value of threshold voltage for a metal-Insulator- semiconductor field-effect translstor made on a single CdS NB can be reduced from ~12.5 to ~0.4V and its transconductance can be increased from~0.2 to~3.2μS by adding an extra Au Schottky contact on the CdS NB, the mechanism of which Is discussed.