A study of the energy loss mechanisms for hot electrons in CdTe and CdS from oscillatory photoconductivity and the magnetophonon effect

Abstract

The energy loss mechanisms for hot electrons are investigated for n-CdTe and n-CdS by means of extrinsic oscillatory photoconductivity, and by the magneto-impurity and magnetophonon effects. With n-CdTe, samples of varying impurity concentrations are studied and it is found that the oscillatory minima occur due to the emission of LO phonons followed by rapid capture at either n=1 or n=2 states of the shallow donor. The first observation of extrinsic oscillatory photoconductivity in n-CdS is reported, with minima found to occur due to capture of electrons at both the band-edge and an excited state of the shallow donor. Magnetophonon and magneto-impurity measurements were performed for CdTe samples of differing impurity concentration. The differences in behaviour found on changing the impurity content in the two experiments is explained in terms of the different electron heating mechanisms in each case.