Automated steady-state admittance spectroscopy for surface studies with application to solar cells

A new technique for automated admittance measurements as a function of frequency and bias has been developed and applied to characterize the insulator-base semiconductor interface of ITO semiconductor-insulator-semiconductor (SIS) solar cells. The system utilizes a computer-controlled automatic network analyzer and represents a significant improvement over impedance bridge and/or lock-in amplifier measurements arising from significantly higher speed with comparable accuracy. The results of and measurements of small indium tin oxide-SiOx-polycrystalline silicon solar cells, which have been used to optimize the fabrication of large-area high-efficiency solar cells are presented and discussed.