Relationship between the conductionhyphen;band discontinuities and bandhyphen;gap differences of InGaAsP/InP heterojunctions

摘要

We have measured the magnitude of the conductionhyphen;band discontinuities at heterojunctions for several compositions of InGaAsP grown lattice matched on InP. We find that the conductionhyphen;band discontinuity (Dgr;Ec) is related to the difference in band gaps (Dgr;Eg) between the InGaAsP and InP layers via Dgr;Ec=0.39(Dgr;Eg). Thus, 40percnt; of the bandhyphen;gap difference lies in the conduction band of this material system. The measurements were made on a series of composition of InGaAsP spanning the alloy range from In0.53Ga0.47As (with energy gapEg=0.75 eV) to InP (Eg=1.35 eV) using capacitancehyphen;voltage techniques. Depletion deep into the semiconductor layers was facilitated by the formation of organichyphen;onhyphen;inorganic semiconductor contact barriers on the InGaAsP surface.