Fabrication and Photovoltaic Measurements of Surface Nanostructure of AlGaInN-Based Photodetector

The photovoltage from a surface nanostructure photodetector was measured at wavelengths of 410 and 388 nm as a function of incident angle. Nanostructure devices were fabricated from the wafer with the light-emitting diode (LED) structure grown by metal organic chemical vapor deposition (MOCVD). A nanopattern was successfully fabricated on the surface of the wafer by a nanoimprint lithography technique. The nanopattern was designed as regular triangles consisting of columns, whose diameter and period were 150 and 300 nm, respectively. The photovoltage between the p- and n-layers of the surface nanostructure photodetector showed 6 or 12 periods when the incident illumination angle was changed. The photovoltage minimums were obtained at 30° off of the direction (1010) of GaN at large incident angle, and this corresponded well to the experimental results obtained from the LED with the same nanopattern.