Low temperature processed metal-semiconductor-metal photodetectors on ZnSe/SI-GaAs (100)
- State Univ. of New York, Amherst, NY (United States)
Low temperature (LT) processed ZnSe MSM photodetectors can be used for detecting gamma rays or X-rays using scintillation crystals in many space and medical applications. Metal-semiconductor-metal (MSM) photodetectors were fabricated on undoped ZnSe grown by molecular beam epitaxy (MBE) on semi-insulating (100) GaAs substrates. The MSM photodetectors consist of interdigitated metal fingers with 2 {micro}m, 3 {micro}m, and 4 {micro}m spacing on one chip. Probimide and SiO{sub 2} thin films were deposited to aid the LT lift-off process before the pattern generation. An interdigitated structure was achieved by photolithography and reactive ion etching. Pd Schottky metal was deposited at a substrate temperature near 77 K using a lift-off technique. The LT metallization provides an improved interface between metal and semiconductor interface. Continuous wave signal to noise ratio (SNR) of 1.57 {times} 10{sup 4} was obtained for 2 {micro}m interdigitated photodetectors, operated under 180 nW optical power at a wavelength of 400 nm. The detectors showed good Dc saturation characteristics indicating a low surface recombination. Saturation current without illumination remained at around less than 1 pA for a {+-} 10 V biasing. Detectors exhibited linearity with light intensity and DC bias voltage suggesting no gain mechanism involved, and showed a high spectral responsivity (0.6 (A/W)) at a wavelength of 450 nm at 5 V applied bias.
- OSTI ID:
- 323891
- Report Number(s):
- CONF-971201-; TRN: 99:004418
- Resource Relation:
- Conference: 1997 fall meeting of the Materials Research Society, Boston, MA (United States), 1-5 Dec 1997; Other Information: PBD: 1998; Related Information: Is Part Of Semiconductors for room-temperature radiation detector applications 2; James, R.B. [ed.] [Sandia National Labs., Livermore, CA (United States)]; Schlesinger, T.E. [ed.] [Carnegie Mellon Univ., Pittsburgh, PA (United States)]; Siffert, P. [ed.] [Lab. PHASE/CNRS, Strasbourg (France)]; Dusi, W. [ed.] [Inst. TESRE/CNR, Bologna (Italy)]; Squillante, M.R. [ed.] [Radiation Monitoring Devices, Inc., Watertown, MA (United States)]; O`Connell, M. [ed.] [Dept. of Energy, Washington, DC (United States)]; Cuzin, M. [ed.] [LETI/CEA, Grenoble (France)]; PB: 681 p.; Materials Research Society symposium proceedings, Volume 487
- Country of Publication:
- United States
- Language:
- English
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