The electronic properties of δ-doped In0.22Ga0.78As/GaAs quantum wells were studied by means of van der Pauw Hall and Shubnikov–de Haas measurements. From the temperature-dependent van der Pauw Hall measurements, two kinds of donor were observed, which had binding energies of 104 and 9.6meV. After inserting In0.1Ga0.9As layers between the In0.22Ga0.78As and GaAs layers, a single donor with binding energy of 50meV was observed. The carrier concentration determined by SdH measurements did not change after the quantum wells were illuminated at low temperature, which indicated that these deep donors could not produce a persistent photoconductivity in delta-doped In0.22Ga0.78As/GaAs quantum wells.

Magnetotransport Study on the Defect Levels of Delta-Doped In0.22Ga0.78As/GaAs Quantum Wells. I.Lo, J.R.Lian, H.Y.Wang, M.H.Gau, J.K.Tsai, J.C.Chiang, Y.J.Li, W.C.Hsu: Journal of Applied Physics, 2006, 100[6], 063712 (5pp)