Measurement of the conduction-band discontinuity in pseudomorphic InxGa1−xAs/In0.52Al0.48As heterostructures

Abstract

Compositional dependence of the conduction-band discontinuity ΔEc in InxGa1−xAs/In0.52Al0.48As pseudomorphic heterostructures has been measured as a function of InAs mole fraction over the range of 0.44≤x≤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 ΔEc with InAs mole fraction x according to ΔEc≊0.384+0.254x for x≤0.54 and an abrupt shift to ΔEc≊0.344+0.487x for x≥0.58. The effects of the conduction-band nonparabolicity and the lattice strain on the Fermi potential have been taken into account in deducing ΔEc from the measured barrier height across the InxGa1−xAs/In0.52Al0.48As heterojunction.

Tight-binding design of intersubband transitions in InGaAs/AlAs quantum heterostructures grown pseudomorphically on InP

“…The band profile was calculated assuming a conduction to valence-band offset ratio of 67:33 between bulks. This value gives a discontinuity of the edge between In 0.52 Al 0.48 As and In 0.4 Ga 0.6 As of 0.40 eV, in agreement with experimental results [13]. The resulting electron potential barrier is 1.33 eV for the central In 0.4 Ga 0.6 As QW, whereas the AlAs X 6c band edge is 0.48 eV above the In 0.4 Ga 0.6 As 6c level.…”

Calculation of Electronic States in Semiconductor Heterostructures with an Empirical spds* Tight-Binding Model

“…While the buffer layers are close to latticematched with the substrate, both the AlAs barriers and the In 0X4 Ga 0X6 As are well characterized by tensile strain, lowering the G and X z band edges in both materials. For the calculation of the band profile, we use now the strain-modified conduction to valence band offset of 67:33, resulting in a discontinuity between the In 0X52 Ga 0X48 As and In 0X4 Ga 0X6 As G edges of 0.40 eV, in agreement with experiment [36]. For the 407 indium concentration used in the central quantum well, the G confinement energy of 1.33 eV is somewhat larger than for the In 0X3 Ga 0X7 As samples discussed before, and from Fig.…”

Admittance spectroscopy measurements on AlInAs/GaInAs/AlInAs quantum well structures: Evidence of a deep level assisted tunneling

“…From the slope of the Arrhenius plot of T/f vs l/r (fig.3 and table I)and using the relation 1, the conduction band discontinuity is derived after the calculation of the Fermi level position and its temperature variation. The values of the conduction band then deduced(Table I) are in good agreement with that obtained from optical (13) and electrical(3)(4)(5)(6)14) measurements. Except for A137 sample, AEc is about 0.51 f 0.02 eV for lattice matched layers, and reaches 0.54 f 0.02 eV for an indium composition of 60%.…”

“…The value of AEc has been determined by few researchers, using capacitance-voltage (C-V) profiling techniques (3) or current-voltage (I-V) characteristics of SIS capacitors on Gal-,InxAs/ Al0.4811105~As (x=0.53) lattice matched layers (4). However, less data are available for the lattice mismatched system (5,6). In the present paper, we report on admittance measurements applied to A10.481n0.52As/ Gal-,InXAs/ A+,.481~.52As single quantum well (SQW) grown on InP, and for the first time evidences are presented for defect assisted tunneling in these structures.…”