Local Ga implantation with focused ion beam and ambipolar lateral carrier transport in strained Si1−xGex /Si quantum wells

Abstract

Lateral carrier diffusion in a strained Si1−xGex/Si quantum well (QW) is reported using a periodic two-dimensional grating geometry defined by focused ion beam local-Ga-implantation. With systematically changing the grating period, we observed a clear dominance switch of steady-state photoluminescence (PL) intensity between defect-related luminescence from Ga-implanted grating stripes and PL emanating from the centered QW region. Fitting to a simple diffusion model, the lateral diffusion length was found to extend to several microns at low temperatures, whereas it increases with temperature up to 58 K.