STARK LOCALIZATION AND MIXING PHENOMENA BETWEEN DIFFERENT STARK-LADDERS IN COUPLED QUANTUM-WELLS

We have studied Stark localization of the minibands in coupled quantum wells by considering the effect of an external electric field, applie d along the growth axis, on a multiple-quantum well system which is id entical to the effect of the ladder-like increment in the potential en ergy. The mixing feature of the Stark ladders is explained by using an analysis of the spatial probability distribution of the carrier. We h ave found that at intermediate ladder values a certain degree of deloc alization of the carrier wave functions exists and finally at large la dder values the Stark-ladder stales become localized within individual wells and a combined band structure occurs. (C) 1995 Academic Press L imited