Photoluminescence studies on Al and Ga interdiffusion across $(Al,Ga)Sb∕GaSb$ quantum well interfaces

The thermal interdiffusion of $AlSb∕GaSb$ multiquantum wells was measured and the intrinsic diffusivities of Al and Ga determined over a temperature range of 823–948 K for 30–9000 s. The 77-K photoluminescence (PL) was used to monitor the extent of interdiffusion through the shifts in the superlattice luminescence peaks. The chemical diffusion coefficient was quantitatively determined by fitting the observed PL peak shifts to the solution of the Schrödinger equation, using a potential derived from the solution of the diffusion equation. The value of the interdiffusion coefficient ranged from $5.2×10−4$ to $0.06nm2∕s$ over the conditions studied and was characterized by an activation energy of $3.0±0.1eV$⁠. The intrinsic diffusion coefficients for Al and Ga were also determined with higher values for Al than for Ga, described by activation energies of $2.8±0.4$ and $1.1±0.1eV$⁠, respectively.