Measurement of valence band edge discontinuity for the InAlAs/GaAsSb heterojunction lattice-matched to InP

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Abstract
The authors describe the measurement of the valence band-edge discontinuity in InAlAs/GaAsSb lattice-matched to InP using the activation energy of a single barrier diode constructed of these materials. It is shown that, near room temperature, the current exhibits an exponential dependence on the inverse temperature, and the activation energy of this behavior is not strongly dependent on any parameter of the system except the band-edge discontinuity. It is further shown that, for small applied voltages, the activation energies have a linear dependence on this voltage which can be extrapolated to an equilibrium value for no applied voltage. The calculated equilibrium value of 640 meV+or-20 meV agrees well with modeled values and with experimentally observed trends. It is therefore believed that this result can be used with a high degree of confidence by device designers and that it demonstrates the great potential of the heterojunction for use in advanced device design.