Abstract

ROSALES-QUINTERO, P. et al. Current conduction mechanisms in n-type α-SiGe: H/p-type c-Si heterojunctions. Superf. vacío [online]. 2008, vol.21, n.2, pp.1-8. ISSN 1665-3521.

n-type α-SiGe:H/p-type c-Si heterojunctions, fabricated with two different base doping concentrations (7×10¹⁷ and 5×10¹⁸ cm^-3) and two thicknesses (37 and 200 nm) for the n-type α-SiGe:H film, were electrically characterized. The current transport mechanisms were determined by analyzing the temperature dependence of the current-voltage characteristics. The electrical measurements show that at low forward bias (V < 0.45 V) the transport mechanisms depend on both the base doping concentration and the thickness of the amorphous film. On the other hand, at higher forward bias (V > 0.45 V) the space-charge limited effect becomes the main transport mechanism for all the measured devices. The increase of both, base doping concentration and layer thickness, leads to an increase of the reverse leakage current. Using high-frequency capacitance-voltage characteristics both type of heterojunctions have shown an abrupt junction behavior. The Anderson rule was used to determine the conduction and valence band discontinuities for these heterojunctions.

Keywords : Amorphous semiconductors; Heterojunction diodes; Transport mechanisms; Leakage currents.

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