Band offset effect on transport in AlxGa1-xAs/GaAs heterojunction bipolar transistors grown by metalorganic chemical vapor deposition

AlxGa1-xAs/GaAs heterojunction bipolar transistors were grown with x in the emitter from 0 to 0.57 and the band offset effect on electron transport has been studied using a new technique. The data, though preliminary, indicate that the transport is dominated by electrons near the conduction-band minima when x < 0.45, but not when x = 0.57.