Mobility modulation in vertical transport of hot electrons in multi-quantum-well structures

Perpendicular mobility of photoexcited electrons in multi-quantum-well (MQW) structures, is modulated by photon energy. The period equals the energy of optical phonons. This theoretical prediction was verified experimentally in ${\mathrm{InPIn}}_{\mathit{x}}$ ${\mathrm{Ga}}_{1\mathrm{-}\mathit{x}}$As MQW’s, proving that in MQW’s the average photocarrier energy is higher than thermal. In bulk material this effect is absent since the thermalization rate is faster than recombination. Monte Carlo simulations render an excellent fit to measured data. A model for the dominant unscreened ionized impurity scattering is presented, upgrading the Conwell-Weskopf theory. © 1996 The American Physical Society.