MAGNETOTRANSPORT PROPERTIES OF 2-DIMENSIONAL CHANNELS IN PSEUDOMORPHIC AND STRAIN RELAXED IN0.17GA0.83AS HETEROJUNCTIONS

The electrical and galvanomagnetic properties of the two-dimensional electron gas present in pseudomorphic In0.17Ga0.83As/Al0.35Ga0.65As and in strain-relaxed In0.17Ga0.83As/In0.15Al0.85As modulation delta-doped heterojunctions were measured as a function of temperature using conventional Hall and resistivity measurements and 1.6 K Shubnikov de Haas oscillatory magnetoresitance measurements, which revealed single subband occupancy. Typical mobilities of the pseudomorphic specimens are, mu(300 K) = 9.3 X 10(3) cm2/V s and mu(1.6 K) = 5.51 X 10(4) cm 2/V s for electron densities, n(s) = 1.07 X 10(12) cm-2 and 9.78 X 10(11) cm-2, respectively. The strain-relaxed structures have higher electron mobilities, mu(300 K) = 10(4) cm-2/V s and mu(1.6 K) = 7.61 X 10(4) cm2/V s for n(s) = 9.37 X 10(11) cm-2 and 8.67 X 10(11) cm-2. Although the total scattering time tau(q) calculated from the magnetic field-dependent amplitudes of their Shubnikov de Haas oscillations, is half that of the pseudomorphic structures, their low temperature, classical relaxation time tau(c) is greater by 30%.