Molecular Beam Epitaxy

28Heterovalent Semiconductor Structures and their Device Applications

Yong‐Hang Zhang

School of Electrical, Computer and Energy Engineering, Arizona State University, Tempe, AZ 85287, USA

28.1 Introduction

The invention of semiconductor heterostructures [1] by Alferov and Kroemer, and superlattices [2] by Esaki and Tsu, ushered in a new era of condensed matter physics, characterized by the discovery of new low‐dimensional phenomena, including quantum confinement, Bloch oscillations [3], and the fractional quantum Hall effect [4,5]. These advances were made possible by epitaxy technologies such as molecular beam epitaxy (MBE) [6] and metal organic chemical vapor deposition (MOCVD) [7], which have enabled technological breakthroughs in areas as diverse as heterojunction bipolar transistors (HBTs), high electron mobility transistors (HEMTs) [8], light‐emitting diodes (LEDs), quantum cascade lasers (QCLs) [9], polariton lasers [10], and quantum‐well infrared photodetectors (QWIPs) [11]. Most of these devices are traditionally based on heterojunctions made of partner materials from the same isovalent and isostructural chemical class, such as group IV/IV (Si/Ge), III–V/III–V (InN/GaN, GaAs/AlAs, GaAs/InAs), or II–VI/II–VI (CdTe/HgTe). However, since many of these devices are very sensitive to misfit dislocations, the choices are limited for material properties, such as bandgaps, band offsets, and refractive indices, when one monolithically integrates all these isovalent semiconductors and ...