Photoluminescence probing of interface evolution with annealing in InGa(N)As/GaAs single quantum wells

The effects of thermal annealing on the interfaces of InGa(N)As/GaAs single quantum wells(SQWs) are investigated by excitation-, temperature-, and magnetic field-dependent photoluminescence(PL). The annealing at 750 \ub0C results in more significant blueshift and narrowing to the PLpeak than that at 600 \ub0C. Each of the PL spectra can be reproduced with two PL components: (i)the low-energy component (LE) keeps energetically unchanged, while the high-energy component(HE) moves up with excitation and shows at higher energy for the In0.375Ga0.625As/GaAs butcrosses over with the LE at a medium excitation power for the In0.375Ga0.625N0.012As0.988/GaAsSQWs. The HE is broader than the corresponding LE, the annealing at 750 \ub0C narrows the LE andHE and shrinks their energetic separation; (ii) the PL components are excitonic, and the InGaNAsshows slightly enhanced excitonic effects relative to the InGaAs SQW; (iii) no typical S-shape evolutionof PL energy with temperature is detectable, and similar blueshift and narrowing are identifiedfor the same annealing. The phenomena are mainly from the interfacial processes. Annealingimproves the intralayer quality, enhances the interfacial In-Ga interdiffusion, and reduces the interfacialfluctuation. The interfacial interdiffusion does not change obviously by the small N contentand hence similar PL-component narrowing and blueshift are observed for the SQWs after a nominallyidentical annealing. Comparison with previous studies is made and the PL measurementsunder different conditions are shown to be effective for probing the interfacial evolution in QWs