Quantum confinement in amorphous InSb

Nanoscale amorphous InSb dots in the range 4–20 nm were grown on glass substrates by simple vacuum thermal evaporation using the low flux rate of 1.5 × 1022 molecules s−1. The energy gaps of amorphous dots determined by optical absorption measurements were found to vary linearly with the inverse square of the dot size indicating the quantum confinement effect. This analysis yields the bulk value of energy gap Eg(bulk) = 0.17 eV for the amorphous phase of InSb and the reduced effective masses μ = 0.0143, which are almost the same as those of the crystalline phase available in the literature.