MEASUREMENT OF THE CONDUCTION-BAND DISCONTINUITY IN PSEUDOMORPHIC INXGA1-XAS/IN0.52AL0.48AS HETEROSTRUCTURES

Compositional dependence of the conduction-band discontinuity DELTA-E(c) in InxGa1-xAs/In0.52Al0.48As pseudomorphic heterostructures has been measured as a function of InAs mole fraction over the range of 0.44 less-than-or-equal-to x less-than-or-equal-to 0.64 using both current-versus-voltage-versus-temperature and capacitance-versus-voltage measurements on semiconductor-insulator-semiconductor structures. The results show a monotonic increase of effective DELTA-E(c) with InAs mole fraction x according to DELTA-E(c) almost-equal-to 0.384 + 0.254x for x less-than-or-equal-to 0.54 and an abrupt shift to DELTA-E(c) almost-equal-to 0.344 + 0.487x for x greater-than-or-equal-to 0.58. The effects of the conduction-band nonparabolicity and the lattice strain on the Fermi potential have been taken into account in deducing DELTA-E(c) from the measured barrier height across the InxGa1-xAs/In0.52Al0.48As heterojunction.