Electron transport in an AlSb/InAs/GaSb tunnel emitter hot-electron transistor

We report preparation of high quality AlSb/InAs/GaSb heterostructures by molecular beam epitaxy. Using this crystal growth technique we have fabricated unipolar AlSb tunnel emitter transistors and used them to explore electron transport as a function of electron injection energy Ei across a 100-Å-thick InAs quantum well base. A low-energy threshold for collector current is observed for Ei>φbc, where φbc is the base/collector potential barrier. A maximum collection efficiency of ∼0.9 is obtained at Ei≂1.5 eV and at larger values of Ei, the collection efficiency decreases due to wave function symmetry and velocity mismatch across the abrupt base/collector heterointerface.