ABSTRACT
Photocurrent (PC) spectra of superlattice p-i-n diodes measured as a function of electric field, lattice temperature and barrier thickness reveal that, in contrast to the normal PC spectra showing positive peaks at ground exciton resonances, the PC intensity is more significantly quenched at resonances than at off resonances under the low field conditions when the barrier is thick. It is found that these negative PC peaks are caused by resonance induced changes of the photogenerated carrier spatial distribution within the relatively thick intrinsic region and by interplay between tunneling escape and radiative recombination. The temperature dependence is rigorously explained by reduced tunneling transport efficiency at higher temperatures due to the thermal saturation of tunneling transport.
