INVESTIGATION OF INGAAS INP INTERDIFFUSION BY SIMULTANEOUS TRANSMISSION ELECTRON-MICROSCOPY AND PHOTOLUMINESCENCE ANALYSIS/

We investigated the interdiffusion of InGaAs/InP quantum wells (QWs) d ue to rapid thermal annealing (RTA) by photoluminescence (PL) spectros copy and wedge transmission electron microscopy (WTEM). After RTA at t emperatures between 650 and 900 degrees C (annealing time 1 min) we ob served large emission energy shifts of up to 210 meV. From the tempera ture dependence of the PL emission energy shifts, the interdiffusion l engths, interdiffusion coefficients and activation energies (e.g. of 2 eV) were determined using a simple model of ion intermixing. In addit ion the samples were characterized by WTEM to obtain a microscopic und erstanding of the interdiffusion process across the InGaAs-InP heteros tructure interface. We obtained a transition region length of about 2. 5 nm for an 11 nm QW, in qualitative agreement with the interdiffusion length obtained from PL spectroscopy. From WTEM analysis the variatio n in chemical composition across the interface was determined, suggest ing lattice-matched interdiffusion.