Quantum confinement effects on the energy gaps of PbSe semiconductor thin films created using electrochemical atomic layer epitaxy

Thin film PbSe semiconductors created using the method of electrochemical atomic layer epitaxy (EC-ALE) were found to exhibit changes in the fundamental energy gap with respect to film thickness. Quantum confinement of the electron-hole pair due to thickness restrictions imposed on PbSe thin films is presumed to be the primary cause of the energy gap changes, which are compared to both parabolic and hyperbolic band theory models of quantum confinement. Transmittance spectra of the thin films were determined from Fourier transform infrared spectroscopy (FTIR), and energy gaps were determined from the analysis of subtle features of the mea-sured absorption coefficient. Atomic force microscopy was employed to study the surface character of the semiconductor thin films, and their future study is recom-mended to involve methods of electron beam lithography and scanning tunneling spectroscopy.