Exciton effects in photoelectromotive force spectra of heterojunctions based on CdSe epitaxial films

Effect of electron-hole interaction on photoemf spectra of the nCdS-n-CdSe heterotransitions in the range of exciton absorption of CdSe epitaxial films has been experimentally investigated. Dependence of the spectra on an external electric field and illuminating has been considered. Possible mechanisms of arising exciton photoemf are analyzed. It is shown that observed peculiarities of photoemf spectrum formation when lighting the heterotransition from opposite sides (appearance of peaks or gaps in the region of exciton absorption) can be attributed to the change of mutual disposition of the spatial charge region and fieldless region of the CdSe film relative to the direction of main light beam