Study of the origin of luminescence in high indium composition InGaN/GaN quantum wells.

We report the emission properties of various InGaN/GaN quantum wells. The photoluminescence of In[sub x]Ga[sub 1-x]N/GaN (x > 20%) quantum wells under varying external bias voltages has been investigated. A redshift of the photoluminescence peak position and decrease of photoluminescence peak intensity with an increase in voltage were observed regardless of the direction of external bias applied. For the sample in which the quantum dot-like region is abundant in quantum well layers, the peak position and intensity were not influenced much by the externally applied bias voltage. The results show that the origin of strong emission from InGaN/GaN quantum wells can be attributed to exciton localization in the quantum dot-like region and they are consistent with those of high-resolution transmission electron microscopy. [ABSTRACT FROM AUTHOR]