Sidewall GaAs tunnel junctions fabricated using molecular layer epitaxy

• Main Author: Takeo Ohno and Yutaka Oyama
• Format: Article
• Language: English
• Published: Taylor & Francis Group 2012-01-01
• Series: Science and Technology of Advanced Materials
• Online Access: http://iopscience.iop.org/1468-6996/13/1/013002

In this article we review the fundamental properties and applications of sidewall GaAs tunnel junctions. Heavily impurity-doped GaAs epitaxial layers were prepared using molecular layer epitaxy (MLE), in which intermittent injections of precursors in ultrahigh vacuum were applied, and sidewall tunnel junctions were fabricated using a combination of device mesa wet etching of the GaAs MLE layer and low-temperature area-selective regrowth. The fabricated tunnel junctions on the GaAs sidewall with normal mesa orientation showed a record peak current density of 35 000 A cm-2. They can potentially be used as terahertz devices such as a tunnel injection transit time effect diode or an ideal static induction transistor.