LOW-TEMPERATURE ADMITTANCE MEASUREMENT IN THIN-FILM AMORPHOUS-SILICONSTRUCTURES

In this paper we analyze low-temperature admittance (capacitance and c onductance) measurement as an effective tool for the characterization of amorphous silicon doped layers embedded in thin film structures. Te mperature and frequency ranges of 20-250 K and 1-100 kHz, respectively , were used. Measurements were performed on p-i silver and p-i-n struc tures. Devices with different thicknesses, carbon, and boron content o f the p-doped layer were examined. The evolution of the conductance of p-i-n solar cells under illumination was also investigated. Results s how excellent sensitivity of the measurement to the states of the dope d layer. This sensitivity is explained by using a finite difference si mulation program, which proves that at low temperature the trapping pr ocess is spatially limited to the doped layers. (C) 1997 American Inst itute of Physics.