Photocurrent and photoluminescence characteristics of networked GaN nanowires

The dark current, photocurrent and photoluminescence (PL) of networked GaN nanowires were characterized in this study. GaN nanowires were synthesized from Ni particles dispersed on an alumina substrate, and subsequent Ti deposition was performed on the as-synthesized GaN nanowires to form electrodes. For the networked GaN nanowires, a significant dark current was observed and the I-V characteristics of the dark current and photocurrent were independent of temperature in magnitude and shape. These results indicate that the GaN nanowires were networked electrically between the electrodes and that the electronic states of these nanowires were degenerate. In addition, the correlation between the photocurrent and PL of the networked GaN nanowires was examined. The characteristics of the green-band emission were similar to those of the photoresponse, and the wavelength range of the green-band emission exactly overlapped that of the below-gap absorption band in the photocurrent spectra. These results indicate that the green emission and the photoresponse have a common origin.