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Title: Modelling of illuminated current–voltage characteristics to evaluate leakage currents in long wavelength infrared mercury cadmium telluride photovoltaic detectors

The current–voltage characteristics of long wavelength mercury cadmium telluride infrared detectors have been studied using a recently suggested method for modelling of illuminated photovoltaic detectors. Diodes fabricated on in-house grown arsenic and vacancy doped epitaxial layers were evaluated for their leakage currents. The thermal diffusion, generation–recombination (g-r), and ohmic currents were found as principal components of diode current besides a component of photocurrent due to illumination. In addition, both types of diodes exhibited an excess current component whose growth with the applied bias voltage did not match the expected growth of trap-assisted-tunnelling current. Instead, it was found to be the best described by an exponential function of the type, I{sub excess} = I{sub r0} + K{sub 1} exp (K{sub 2} V), where I{sub r0}, K{sub 1}, and K{sub 2} are fitting parameters and V is the applied bias voltage. A study of the temperature dependence of the diode current components and the excess current provided the useful clues about the source of origin of excess current. It was found that the excess current in diodes fabricated on arsenic doped epitaxial layers has its origin in the source of ohmic shunt currents. Whereas, the source of excess current in diodes fabricated on vacancy doped epitaxialmore » layers appeared to be the avalanche multiplication of photocurrent. The difference in the behaviour of two types of diodes has been attributed to the difference in the quality of epitaxial layers.« less
Authors:
 [1] ; ;  [2]
  1. Institute of Defence Scientists and Technologists, CFEES Complex, Brig. S. K. Majumdar Marg, Delhi 110054 (India)
  2. National Laboratory for Infrared Physics, Shanghai Institute of Technical Physics, Chinese Academy of Sciences, Shanghai 200083 (China)
Publication Date:
OSTI Identifier:
22402638
Resource Type:
Journal Article
Resource Relation:
Journal Name: Journal of Applied Physics; Journal Volume: 116; Journal Issue: 18; Other Information: (c) 2014 AIP Publishing LLC; Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; ARSENIC; CADMIUM; DOPED MATERIALS; ELECTRIC POTENTIAL; EPITAXY; LAYERS; LEAKAGE CURRENT; MERCURY; PHOTOVOLTAIC EFFECT; TELLURIDES; TEMPERATURE DEPENDENCE; THERMAL DIFFUSION; TOWNSEND DISCHARGE; TUNNEL EFFECT; VACANCIES; WAVELENGTHS