The effects of thermal annealing on C-doped InGaAs/AlGaAs quantum well laser structures capped with TiO2 layers were investigated. The atomic interdiffusion was greatly suppressed by the presence of a TiO2 capping layer during annealing, inhibiting even the thermal intermixing observed in the uncapped sample. An increase in the amount of lattice contraction associated with the presence of substitutional C CAs after annealing without a capping layer was observed, but not after annealing with a TiO2 capping layer. Capacitance–voltage measurements confirmed the electrical activation of C after annealing without a dielectric layer and showed a negligible change after annealing using a TiO2 capping layer. The possible mechanisms involving both the atomic intermixing on the group III sub-lattice and C activation on the group V sub-lattice and the implications for opto-electronic device integration using impurity-free intermixing were considered.

Suppression of Thermal Atomic Interdiffusion in C-Doped InGaAs/AlGaAs Quantum Well Laser Structures using TiO2 Dielectric Layers. P.L.Gareso, M.Buda, L.Fu, H.H.Tan, C.Jagadish: Applied Physics Letters, 2004, 85[23], 5583-5