Broadly tunable cubic phase InGaN/GaN quantum wells grown by metal-organic chemical vapor deposition.

Conventional c-plane wurtzite InGaN/GaN quantum wells are subject to a large internal field that acts to separate electrons and holes and thereby lowers the rate of radiative recombination. This effect is exacerbated for higher indium contents and so may contribute to the lower efficiency of c-plane wurtzite InGaN/GaN QWs when emitting at green and amber wavelengths. In comparison, InGaN/GaN QWs grown in the cubic zincblende phase along the (001) direction are free of such fields and so exhibit recombination lifetimes that are shorter by two orders of magnitude and independent of indium content. Here, we report on zincblende QWs grown by metal-organic chemical vapor deposition at different temperatures. This results in different indium contents and thereby allows tuning of the emission band from blue to yellow. For each indium content, the spectrally integrated emission quenches as the temperature rises. However, the ratio of room temperature to low temperature emission improves for higher indium contents, increasing from 18% to 34% as the emission peak is tuned from 2.8eV to 2.1eV. This behavior is attributed to the thermal escape of carriers from the QWs playing an important role in the temperature dependent quenching of emission.