Growth mode control of InGaN on GaN by using SiH₄ post-treatment

We report on a way to control the growth mode of an In_0.43Ga_0.57N layer on GaN by using SiH₄ post-treatment. In_0.43Ga_0.57N islands were formed on the GaN layers by a using Stranski-Krastanov growth mode without SiH₄ post-treatment. When the SiH₄ flow rate was increased from 0 to 10 sccm, the InGaN island density decreased from 3.3 × 10⁹ to 1.9 × 10⁹ then to zero, resulting in two-dimensional growth. However, a further increase in the SiH₄ flow rate to 15 sccm again led to the formation of InGaN islands. Temperature- and excitation-power-dependent photoluminescence spectra showed that the InGaN islands provided strong localized recombination centers for electrical charge carriers and that the InGaN layers were composed of InGaN islands with different numbers of monolayers. This abnormal growth behavior with SiH₄ post-treatment was explained by the combined effects of surfactant-mediated growth modification and the formation of Si_xN_y with the injection of SiH₄.