Bulg. J. Phys. vol.33 no.s3 (2006), pp. 223-228

An Alternative Approach for Determining the Semiconductor Type Based on SPV Phase Spectral Measurements

K. Kirilov, Ts. Ivanov, V. Donchev, K. Germanova
University of Sofia, Faculty of Physics, 5 James Bourchier Blvd., BG-1164 Sofia, Bulgaria
Abstract. An original approach is proposed for determining the band bending direction (up or down) in semiconductor samples as an alternative of the contact potential difference approach [1]. It is based on measurements of surface photovoltage (SPV) phase spectra in metal-insulator-semiconductor structures under super-bandgap excitation. It is shown that the spectrum of the SPV phase, measured in a correct way, reveals a bandgap-related knee. For downward (upward) band bending, this knee corresponds to an increase (decrease) of the SPV phase modulus towards 180° (towards 0°). Thus the SPV phase can be used as a handy tool for determining the semiconductor type. The proposed approach has been demonstrated in the simplest case of surface band bending in bulk p-type Si and n-type GaAs with free surfaces.

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