Ultraviolet (UV) photoconductive detectors based on InxAlyGa1-x-yN quaternary alloy lattice-matched to GaN have been fabricated and characterized. The detectors consisted of about 0.1 μm thick InxAlyGa1-x-yN quaternary alloy of different In (x) and Al (y) compositions grown by metalorganic chemical vapor deposition (MOCVD). The films were characterized by different techniques including x-ray diffraction (XRD), Rutherford backscattering spectroscopy (RBS), atomic force microscopy (AFM), Hall-effect and time-resolved photoluminescence measurements. The characteristics of these UV detectors including the cut-off wavelength, photoresponsivity and device speed have been measured. The cut-off wavelength of the InxAlyGa1-x-yN detectors was found to vary to the deep UV range with varying In and Al compositions. The most important and intriguing result is that the responsivity of the InxAlyGa1-x-yN quaternary alloy exceeded that of AlGaN alloy of comparable cut-off wavelength by a factor of five. This makes the nitride quaternary alloy very important material for solar blind UV detector applications in the deep UV range where Al rich AlGaN alloy have problems with low quantum efficiency and cracks due in part to lattice mismatch with GaN.
|Journal||Materials Research Society Symposium - Proceedings|
|State||Published - 2001|
|Event||GaN and Related Alloys 2000 - Boston, MA, United States|
Duration: Nov 27 2000 → Dec 1 2000