Published online by Cambridge University Press: 25 February 2011
A dense network structure with low defect and void densities in a-SiGe:H alloys are realized by remote deposition conditions (triode reactor configuration, H2-dilution of SiH4+GeH4 gas mixture). The material properties are characterized by optical transmission, photothermal deflection spectroscopy (PDS), scanning electron microscopy (SEM), and space charge limited currents (SCLC). A high refractive index n∞. (λ->∞) and a fine surface structure in SEM images indicate an optical dense network, moreover the defect density determined by SCLC is reduced in comparison to films deposited in a conventional diode reactor. The substrate temperature TS, one of the key parameters for high quality low gap material, sensitively influences the optical and electronic properties of the samples. The optimum substrate temperature (TS≍=225°C) is found to be lower than for the deposition of a-Si:H (TS≍250°C).