Responsivity of porous silicon for blue visible light with high sensitivity

Iftikhar M Ali

doi:10.30723/ijp.v16i37.81

Abstract

In this work, porous silicon (PS) are fabricated using electrochemical etching (ECE) process for p-type crystalline silicon (c-Si) wafers of (100) orientation. The structural, morphological and electrical properties of PS synthesized at etching current density of (10, 20, 30) mA/cm2 at constant etching time 10 min are studied. From X-ray diffraction (XRD) measurement, the value of FWHM is in general decreases with increasing current density for p-type porous silicon (p-PS). Atomic force microscope (AFM) showed that for p-PS the average pore diameter decreases at 20 mA. Porous silicon which formed on silicon will be a junction so I-V characteristics have been studied in the dark to calculate ideality factor (n), and saturation current (Is) for these junctions. These junctions are used in photo sensors applications, where the photo sensors have been examined at blue light region. Sensitivity, rise and fall times have been calculated for this wavelength, the maximum value for sensitivity is (3797.6 %) at etching current density 10 mA/cm2 under blue light illumination at zero bias voltage.

Highlights

Porous silicon is an interesting and versatile optical material that is fabricated by electrochemical etching of silicon
X-ray diffraction (XRD) patterns show the formation of porous silicon where the strong peak of Si is observed at 2θ = 68.002o to p-type for (100) direction
The broadening in this peak proves the nanosize effect where the large value of full width at half maximum (FWHM) (2.5230) at 10 mA/cm2 may be due to the small crystallites that illustrate there is a control on the nanosize of porous layer

Summary

Introduction

Porous silicon is an interesting and versatile optical material that is fabricated by electrochemical etching of silicon. The formation of porous layer results in lattice expansion or the strain that caused by the effect of nanostructure that make small shift in the peak positions [12] We show that there is SiO2 phase which proves the formation of porous silicon. I-V characteristics for p-PS in the dark The dark I–V characteristics at different current densities of (10, 20, 40) mA/cm at constant etching time of

Dark state

Findings

Conclusions