Fotocondutividade em a-Ge:H dopado com elementos da coluna III da Tabela Periodica

AUTOR(ES)
DATA DE PUBLICAÇÃO

1997

RESUMO

This work reports on the effects of gallium and indium p-type doping on the photoconductivity of hydrogenated amorphous germanium ( a-Ge:H ) thin films deposited by the rf-sputtering method. The quantum efficiency-mobility-lifetime ( hmt ) product has been measured at room temperature as a function of the dark Fermi energy EF on samples with relative dopant concentration range between ~ 3x10-5 and ~ 10-2. A decrease of hmt is observed with the increase of the gallium concentration till a minimum is reached for samples near the compensation level (NGa/NGe ~ 3x10-4), when hmt is about 16 times lower than the value obtained for intrinsic samples. This behavior is followed by an hmt increase of aproximately 4 times at concentration levels between compensation and NGa/NGe ~ 1.5x10-3. Then, for higher gallium concentrations, hmt decreases again. For In-doped samples, a monotone decrease of hmt is measured for all the impurity concentration range. These results are consistent with a "standard" model for the defects, which assumes that the dangling bond is the main recombination path. A qualitative explanation was obtained where the changes in the occupancy of the charged defect states in the mobility gap due to doping are taken into account.

ASSUNTO(S)

semicondutores amorfos efeito fotovoltaico fotocondutividade

ACESSO AO ARTIGO

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