Structural, optical, and electrical characterization of improved amorphous hydrogenated germanium

High‐quality amorphous hydrogenated germanium has been deposited using the diode rf glow discharge method out of a gas plasma of GeH4 and H2. The optical, electrical, and structural properties of this material have been extensively characterized. The optical and electrical properties are all consistent with material containing a low density of defect related states in the energy gap. In particular, this material has an ημτ=3.2×10−7 cm2/V, ratio of photocurrent to dark current of 1.3×10−1, and flux dependence of the photocurrent with γ=0.79 at 1.25 eV measured using photoconductivity, a μτ=4×10−8 cm2/V measured using time of flight, an Urbach energy of 51 meV and α at 0.7 eV of 8.3 cm−1 measured using photothermal deflection spectroscopy, a dangling bond spin density of 5×1016 cm−3 measured using electron spin resonance, photoluminescence with a peak energy position of 0.81 eV and full width at half maximum of 0.19 eV, an activation energy of 0.52 eV and σ0 of 6.1×103 (Ω cm)−1 measured using dark conductiv...