Structural and electrical properties of polycrystalline Ge films

Abstract

Structural and electrical properties of crystalline Ge films deposited at 723 K on glass substratee and crystallized Ge films obtained by crystallizing the amorphous films by heating at 723 K ars investigated. The films are polycrystalline with small grain size (≈620 Å in crystalline films and ≈100 Å in crystallized films). Both the films show p-type behaviour. The observed temperature dependence of the carrier concentration is theoretically analyzed which shows the existence of an acceptor level at about 0.05 eV above the valence band. The mobility of charge carriers is analyzed in terms of various scattering mechanisms. Grain boundary scattering is found to be the dominant scattering mechanism in these films. The potential barrier associated with grain boundary scattering is calculated to be 1.0×10^-2 eV in crystalline and 2×10^-2 eV in crystallized films.