Carrier-induced dynamic strain effects in semiconductor nanocrystals

In this pa per, we reveal, for the fi rst ti me, the basic nature of electr on-phonon interaction in semiconductor nanocrystals. On the basis of the ex perimental results on GaAs, GaP, Si nanocrystals, and porous silicon, we fu rther prove that the carrier-induced dynamic strain effect (CIDSE) is a com mon feature in solids, wh ich plays an extremely im porta nt role on the el ectronic and optical properties of semiconductor nanocrystals. The optical transitions in semiconductor nanocrystals are dominated by multiphonon-assi sted electronic transition processes. Nanocrystals with direct-gap and a la rge pressure coefficient for the ba nd gap (as GaAs) no longer show band-ed ge emission due to the intrinsic strong electron - long wavelength anharmon ic acoustic phonon coupling. Nanocrystals with an indirect-gap show a carri er-induced dynamic Jahn-Teller effect and two fairly strong intrinsic emiss ion bands. Most of the open questions in the semiconductor nanocrystal fiel d, including porous silicon, can be consistently explained by the carrier-i nduced dynamic strained quantum dot model. (C) 1998 Kluwer Academic Publish ers.