Study of anomalous behavior of steady state photoconductivity in highly crystallized undoped microcrystalline Si films

The photoconductivity (σph) of highly crystallized dense undoped hydrogenated microcrystalline silicon (μc-Si:H) films was measured as a function of light illumination over a wide temperature range (∼15-325 K). A thermal quenching behavior in σph was observed at ∼240 K. The photoconductivity exponent (γ) was found to be sublinear with γ as low as 0.13. A density of states (DOS) profile having a steep conduction band tail, and valence band tail with two distinct distributions was found to be necessary to understand the electronic transport behavior in the inherently heterogeneous μc-Si:H films.