Micro-photoluminescence study of InxGa1–xN/GaN quantum wells

In micro-photoluminescence (PL) study of a green InxGa1–xN/GaN single quantum well at room temperature, we observed some areas in the sample where only weak blue emission was detected. One of the difficulties in obtaining high quality InxGa1−xN/GaN quantum wells is the large difference in optimum growth temperatures for InxGa1–xN and GaN. By decreasing the growth temperature of GaN barriers in violet InxGa1–xN/GaN quantum wells, the PL emission was observed to be weaker for lower excitation density, but stronger for higher excitation density. It is emphasized that optical characterization under high excitation density is necessary for device applications such as laser diode structures.