Evaluation of wavelength shifts of green and blue light emitting diodes with InN/GaN multiple quantum wells

Abstract

InN/GaN multiple quantum wells were grown by metalorganic chemical vapor deposition. The structural and electrical properties were characterized by transmission electron microscopy and electroluminescence measurements. From the transmission electron micrographs, it was shown that the well layer was grown like a quantum dot. The well layer is expected to be the nano-size structures in the InN multiple quantum well layers. The multi-photon confocal laser scanning microscopy was used to investigate the optical properties of the light emitting diode structures with InN active layers. It was found that the two-photon excitation was possible in InN system. The pit density was measured by using the far-field optical technique. In the varied current conditions, the blue light emitting diode with the InN multiple quantum well structures did not have the wavelength shift. With this result, we can expect that the white light emitting diodes with the InN multiple quantum well structures do not show the color temperature changes with the variations of applied currents.