An investigation was made of the interdiffusion dynamics in self-assembled InAs/InP(001) quantum dots subjected to rapid thermal annealing at 600 to 775C. Two quantum dot samples, capped with InP grown at either optimal or reduced temperatures to induce grown-in defects, were compared. Atomic interdiffusion was assessed by using photoluminescence measurements in conjunction with tight-binding calculations. By assuming Fickian diffusion, the interdiffusion lengths, LI, were determined, as a function of annealing conditions, from a comparison of the measured optical transition energies with those calculated for InP/InAs1−xPx/InP quantum wells with graded interfaces. The LI values were then analyzed by using a 1-dimensional interdiffusion model that accounted for both the transport of non-equilibrium concentrations of P interstitials from the InP capping layer to the InAs active region and the P-As substitution in the quantum-dot vicinity. It was demonstrated that each process was characterized by an Arrhenius relationship. The activation energy and pre-exponential factor for P interstitial diffusion in the InP matrix were E = 2.7eV and D = 103.6cm2/s; which were independent of the InP growth conditions. For the P-As substitution process, E = 2.3eV and (co/no)D was between 10−5 and 10−4cm2/s; depending upon the quantum-dot height and the concentration of grown-in defects (co/no).

Effects of Grown-In Defects on Interdiffusion Dynamics in InAs/InP(001) Quantum Dots Subjected to Rapid Thermal Annealing. C.Dion, P.Desjardins, N.Shtinkov, F.Schiettekatte, P.J.Poole, S.Raymond: Journal of Applied Physics, 2008, 103[8], 083526