Growth of III-nitrides on Si(111) and its application to photodiodes

In this paper, we investigated growth of GaN and Al0.09Ga0.91N epilayer grown on silicon (111) by using II MBE system. The major characterization tools used for this study were high resolution X-ray diffraction (HRXRD), and micro photoluminescence (PL) spectroscopy. Also reported is our attempt to fabricate and characterize metalsemiconductor-metal photodiode based on these films. The responsivity as a function of wavelength for an MSM GaN/Si(111) detector is a sharp cut-off wavelength at 362 nm. A maximum responsivity of 0.256 A/W was achieved at 358 nm. For Al0.09Ga0.91N film, there is a sharp cut-off wavelength at 340 nm. A maximum responsivity of 0.263 A/W was achieved at 338 nm. In UV spectral region, the detector shows a little decrease from 340 to 200 nm. The responsivity of the MSM drops by nearly an order of magnitude across the cut-off wavelength.