Effect of Rapid Thermal Annealing on Photoluminescence Properties of Low-Temperature Grown InGaAs/GaAs Multiple Quantum Wells

Abstract

Samples having In0.12Ga0.88As/GaAs multiple quantum well (MQW) structures were grown by molecular-beam epitaxy at substrate temperatures ranging from a normal temperature of 550 °C to a low temperature of 250 °C. When the samples were grown with low As4/Ga beam equivalent pressure ratios of 5–6, photoluminescence (PL) was observed in spite of low growth temperatures of 250–300 °C. Furthermore, after rapid thermal annealing (RTA) at approximately 900 °C, the intensities of PL from the samples grown at 300 and 250 °C were improved so as to become comparable to that from the as-grown sample grown at 550 °C. At the same time, the RTA caused blue shifts in PL peak energy for these low-temperature grown samples. From the shifts in PL peak energy, the diffusion length of In–Ga interdiffusion was estimated to be approximately 4 nm for the 900 °C RTA and the activation energy was estimated to be 2.2 ±0.6 eV in these low-temperature grown samples.

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

“…15,16 To improve the optical quality, either in situ annealing or post-growth rapid thermal annealing (RTA) is necessary, at the expense of a wavelength blueshift. 17 As PL is more sensitive to the change in composition profile than other methods, such as X-ray diffraction, 18,19 it was frequently used for clarifying the blueshift. 20,21 The evolution of PL peak energy manifested pronounced S-shape for the dilute-N InGaNAs/GaAs single quantum wells (SQWs) at low temperatures, and followed the empirical Varshni model in the high-temperature region with significant reduction in the temperature dependence as compared to the N-free sample.…”