Point admittance spectroscopy: New PV diagnostic

Typical admittance (e.g., capacitance-voltage-frequency) measurements are essentially one-dimensional measurements, characterizing an electronic device in the transverse dimension between its electrodes [1],[2]. Here, we discuss situations in which one of the electrodes has very small dimensions so that the device surface is not at equipotential and lateral dimensions influence the measurement. This point admittance spectroscopy (PAS) approach opens new venue in characterizing PV devices before their final metallization. We analyze the equivalent circuit and conduct numerical modeling underlying PAS. We show that the admittance technique is sensitive to lateral nonuniformities and the existence and location of shunts, and may also be used to determine a system lump parameters, such as series resistance, shunt resistance, and open circuit voltage.