Proposed GaAs and Si OPFET Photodetectors for Solar Cell Applications

The potential of the GaAs and Si-based Optical Field Effect Transistor (OPFET) photodetectors for use in solar cell applications has been examined. The solar power spectrum with the air mass (AM0) suitable for satellite and space vehicle applications is provided as an input. The detectors closely reproduce the input spectrum while delivering sufficient output current with high responsivity, External Quantum Efficiency (EQE), and low switching times. These parameters along with the photovoltage generated as a function of wavelength are plotted and deeply analyzed. The comparative study of the Si and the GaAs OPFET detectors is presented. The analysis is based on the structural, material parameters, and the external factors applied. The gate materials utilized are Indium-Tin-Oxide (ITO) for Si and gold (Au) for GaAs. Two distinct illumination models: Buried-gate front-illuminated OPFET and the generalized model of OPFET are being considered for the study. The proposed devices show great potential for solar cell applications.