Spectral Current Density and Responsivity Scaling for Fourier Transform Photocurrent Spectroscopy

TL;DR

This paper introduces two methods for scaling photocurrent spectral density in Fourier Transform Photocurrent spectroscopy and demonstrates their effectiveness on semiconductor sensors, enabling more accurate spectral measurements.

Contribution

The paper presents novel methods to accurately scale photocurrent spectral density and responsivity in FTPC spectroscopy, verified through experimental validation.

Findings

Effective scaling of photocurrent spectral density achieved

Identification of impurity-band and interband transitions in SiC sensors

Methods applicable to calibrated and weak responsivity devices

Abstract

We propose and experimentally verify two methods to scale arbitrary units to photocurrent spectral density (A/eV) in Fourier Transform Photocurrent (FTPC) spectroscopy. We also propose the FTPC scaling to responsivity (A/W), provided a narrow-band optical power measurement is available. The constant background of the interferogram provides a precise determination of the photocurrent spectral density. The second method relies on the scaled amplitude of the interferogram. Although the latter method leads to more significant errors, it still provides good order of magnitude estimates of the total photocurrent. We demonstrate the technique on a calibrated InGaAs diode and weak responsivity SiC interdigital sensors. We identify a series of impurity-band and interband transitions in the SiC sensors.