Dopagem tipo-n e mudanças estruturais induzidas pelo nitrogenio de filmes de germanio amorfo hidrogenado

AUTOR(ES)
DATA DE PUBLICAÇÃO

1998

RESUMO

In this work several informations are presented and discussed about structura1 and optoelectronic properties of doped samples of hydrogenated amorphous germanium (a-Ge:H) using P, As (solid sources) and N (using NH3) as doping impurities. In addition, we studied structura1 changes of a-Ge:H induced by N, in the nitrogen concentration range of ~2-6 at. %. The samples were deposited by rf- sputtering and characterized by Photothermal Deflection Spectroscopy (PDS), optical transmission spectroscopy in the Near InfraRed- Visible and lnfraRed and measurements of dark conductivity. With respect to doping, the active doping of a-Ge:H was confirmed for the first time by using solid sources of P and As as impurities. We observed activation energy changes about ~0.3 eV and a room temperature conductivity increase of about ~3 orders of magnitude for the three impurities used. Arsenic showed to be the less efficient dopant. In relation with the second study, we found the preferential incorporation of N as NH and NH2 radicals and we suggest that these radicals induce the creation of cavities in the material. We observed for the first time a shift of the vibration frequency of a-Ge:H stretching surface-like to lower energies, this fact was explained as being due to decreasing of the average void volume as a function of the nitrogen concentration

ASSUNTO(S)

arsenio nitrogenio fosforo germanio semicondutores amorfos

ACESSO AO ARTIGO

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