Published online by Cambridge University Press: 21 February 2011
A-Si : H and a-Si : H/a-SiGe : H heterojunctions have been prepared as the photoconductors in the liquid crystal light valves. The impedance matching conditions of the a-Si : H and the heterojunction in the valves have been carefully analysed, which has shown that the adjustment for the capacitance of the photoconductor is the key procedure for the matching, but the low photocapacitance effect in the a-Si : H limits the further improvements on the matching. The formation of the a-Si : H/a-SiGe : H diode promotes the photocapacitance effect in the photoconductor, and the matching behavior in the valve is greatly improved.