Enhancing the Electrical Properties of Porous Silicon Photodetector by Depositing MWCNTs

Abstract

In the present work, multiwall carbon nanotubes (MWCNTs) layers dispersed in DMF and citric acid deposited by drop casting on porous silicon (PSi) photodetector have been prepared by electrochemical etching (ECE) process at 25 mA/cm2 for 20 min. X-ray diffraction (XRD), atomic force microscopy (AFM), Fourier transformation infrared spectroscopy (FTIR), energy dispersive X-ray (EDX), current–voltage (I-V) characteristics, capacitance-voltage(C-V) characteristics, spectral responsivity (Rλ) and specific detectivity (D*) before and after depositing MWCNTs layers were investigated. It was found that, the On/Off ratio was increased after depositing MWCNTs, while ideality factor and built in potential were decreased and this fact indicates that Al/PSi/c-Si/Al photodetector was nearly approaching the ideal diode characteristic after deposition process. Significant enhancement in spectral responsivity and specific detectivity were also noticed after depositing MWCNTs on porous matrix.