Effects of conduction band offset on two-dimensional electron gas in delta-doped InGaAs-based heterostructures

Electron transport properties of delta-doped AlInAs/InGaAs and AlAsSb/InGaA s heterostructures lattice-matched to InP substrates are investigated using the Shubnikovde Haas oscillations and the Hall effect. The Fast Fourier tr ansform of the magnetoresistance shows that both the ground and first excit ed subbands in the InGaAs channel are occupied. The mobility in the second subband is higher than that in the first subband in both heterostructures. This is attributed to the fact that electrons in the first subband are, on average, closer to the interface and are therefore scattered more strongly by ionized impurities, The dependence of the mobility on carrier concentrat ion suggests that intersubband scattering rate is more dominant in structur es with higher conduction band offsets. Alloy scattering, on the other hand , is found to be more dominant in the higher band offset system.