PHOTOSENSITIZATION EFFECTS OF PORPHYRIN ON N-SI(111) AND N-GAAS(100)

Photosensitization effects of 5,10,15,20-tetrakis-(4-trimethylaminephe nyl) porphyrin tetraiodide(TAPPI) on n-Si(111) and n-GaAs(100) were st udied by surface photovoltage spectroscopy. n-Si can be sensitized onl y in the Soret band absorption region of the TAPPI molecule, n-GaAs ca n be sensitized in the whole irradiation region (h nu > E-g). The diag rams of energetic level correlation between the TAPPI molecule and the two semiconductor substrates were determined by cyclic voltammetric m easurement and, on the basis of them, the different photosensitization effects of TAPPI on n-Si and n-GaAs are explained reasonably. (C) 199 8 Elsevier Science S.A.