Organic-on-Inorganic Ag/n-GaAs/p-CuPc/Ag Photoelectric Sensor

Kh.S.Karimov1, Kh.M.Akhmedov1, A.A.Dzhuraev1, M.N.Khan2, S.M.Abrarov2, M.I.Fiodorov3

1Physical Technical institute of Academy of Sciences, Rudaki Ave.33, Dushanbe, 734025, Tajikistan.

2GIK Institute of Engineering Science and Technology, Topi, Swabi, N.W.F.P., Pakistan, 23460.

3State Technical University, Vologda, Russia.

Abstract

A thin organic film of copper phthalocyanine (CuPc) as p-type semiconductor was deposited by vacuum evaporation on to n-type GaAs single-crystal semiconductor substrate. An investigation was made of photoelectrical and rectification properties of organic-on-inorganic pn (anisotype) heterojunction Ag/nGaAs/pCuPc/Ag photoelectric sensor. Photoelectric characteristics were measured in operation of the sensor in photo-voltaic mode (as solar cell) and photo-conduction mode (as photodiode) under tungsten filament lamp illumination and in photo-voltaic mode under solar radiation and semiconductor injection laser beam illumination (l=650 nm). In latter case it was investigated frequency response of the sensor in the range of 15000 Hz. Rectification ratio determined from dark IV curves was 54 at 0.5 V voltage, threshold voltage at forward bias was 0.3 V. Photo-current and photo-voltage spectra showed that sensor are sensitive in the large spectral range of wavelengths 200-1000 nm, from UV to Visible and IR.