Single ultra-thin InAs insertions in GaAs were investigated by means of deep-level transient Fourier spectroscopy and capacitance-voltage measurements near to the transition from layer-by-layer growth to 3-dimensional growth. The formation of a broad band of deep levels, between 0.60 and 0.80eV below the GaAs conduction band edge, was shown to be related to the incorporation of a strained InAs layer. The defect density could be as high as 5 x 1010/cm2. Distinct interfacial levels, whose formation was related to the GaAs growth conditions, were found at the position of the ultra-thin InAs sheet. Due to their short-range potential, these interfacial deep-level defects were suitable for probing the local properties of ultra-thin InAs inserts.

Deep and shallow electronic states at ultra-thin InAs insertions in GaAs P.Krispin, J.L.Lazzari, H.Kostial: Journal of Applied Physics, 1998, 84[11], 6135-40