Electron transport in AlSb/InAs/GaSb tunneling hot-electron transistor

Summary form only given. The authors recently (1987) demonstrated room-temperature operation of a unipolar AlSbAs/InAs/GaSb double-heterojunction HET (hot-electron transistor) with a two-dimensional electron gas forming the base region. In the present work, they report first results of using an AlSb tunneling emitter barrier to explore electron transport as a function of electron injection energy E_i across a 100-AA-thick InAs quantum-well base in a similar device. The tunneling process in the present device ensures that a monoenergetic beam of electrons is injected with small angular spread. A sharp low-energy threshold for the collector current is observed for E_i greater than the base/collector potential barrier Phi _bc=0.8 eV. Maximum collection efficiency of about 0.9 occurs at E_i=1.5 eV. With further increase in E_i, collection efficiency decreases to less than 0.5 for E_i=2.5 eV. A qualitative understanding of this behavior can be obtained by examining the InAs and GaSb band structures. An important mechanism affecting the collection efficiency is quantum reflection from Phi _bc, which is determined by electron velocity mismatch across the interface.