Photoemission and photon-enhanced thermionic emission: Effect of jump in electron mass

The effect of jump in electron mass on the electron transfer through interfaces with positive and negative potential steps is considered in relation with practically important photoemission and photon-enhanced thermionic emission from semiconductors with positive and negative effective electron affinities. For a zero potential step, a direct similarity is established between the expressions for electron reflection and transmission and Fresnel equations for p-polarized light, with the ratio of masses replacing the ratio of dielectric constants. For non-zero potential steps of both signs, due to the jump in mass, there are critical electron energies that separate the energy regions with qualitatively different angular dependences of the transmission coefficient. The influence of the jump in mass on the spectra of photoemission quantum yield, which are measured experimentally under transition from negative to positive electron affinity at the p-GaAs(Cs,O)-vacuum interface, is considered. It is shown that, for a decisive proof of the jump-in-mass contribution to the electron transfer through semiconductor-vacuum interface, measuring the energy and angular distributions at the state of positive electron affinity is more advantageous, as compared to the state of negative electron affinity.