FORWARD CURRENT TRANSIENTS IN AMORPHOUS-SILICON P-I-N STRUCTURES

The transient forward current in several specimens of a-Si:H p-i-n structures was studied as a function of applied voltage, temperature, and illumination as well as the degradation of the samples. The results show that the delay time of the current onset from its initial decay relates to the initial electron space-charge-limited current with a power law, t(d) proportional to(I-SCLC)(-gamma), where gamma is a constant which is insensitive to the measurement conditions such as temperature and illumination but depends on the properties of devices such as the density of states in the intrinsic layer. Therefore, the value of gamma is a measure of the quality of devices. The current-response time product, I(f)t(r), is largely independent of the applied voltage for specific samples.