The impact of laser energy on the photoresponsive characteristics of CdO/Si visible light photodetector
Mohamed Bashir Ali Bashir, Ethar Yahya Salih, Altaf Hussain Rajpar, Ghazaleh Bahmanrokh, Mohd Faizul Mohd Sabri
Abstract
Abstract In this article, cadmium oxide (CdO) was deposited using pulsed laser deposition approach on porous silicon (Si) wafer for visible light photodetector application, through which a series of devices were proposed as a function of the deposition energy. The microstructural as well as optical characteristics of the prepared film/s were demonstrated, respectively, using x-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and ultraviolet visible light spectroscopy (UV–Vis) analysis. In details, the UV–Vis analysis revealed the occurrence of optical band gaps within the range of 2.38–2.42 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>eV</mml:mtext> </mml:mrow> </mml:math> , while an average nanoparticle diameter was found to be 45 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>nm</mml:mtext> </mml:mrow> </mml:math> using FE-SEM technique. This in turn demonstrated a sound relation with the photoresponsive behavior of the attained photodetectors. A photoresponsivity and specific detectivity of 1.9 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi>μ</mml:mi> <mml:mrow> <mml:mtext>A</mml:mtext> </mml:mrow> <mml:mrow> <mml:mtext>m</mml:mtext> </mml:mrow> <mml:mrow> <mml:msup> <mml:mrow> <mml:mtext>W</mml:mtext> </mml:mrow> <mml:mrow> <mml:mo>−</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> and <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mn>1.21</mml:mn> <mml:mo>×</mml:mo> <mml:mrow> <mml:msup> <mml:mn>10</mml:mn> <mml:mn>9</mml:mn> </mml:msup> </mml:mrow> </mml:math> Jones were attained using 700 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>mJ</mml:mtext> </mml:mrow> </mml:math> laser energy. In the meanwhile, the estimated response/recover time of the addressed laser energy was found to be 300 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>s</mml:mtext> </mml:mrow> </mml:math> and 340 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mrow> <mml:mtext>s</mml:mtext> </mml:mrow> </mml:math> , respectively. The photo-responsive characteristics of the fabricated devices were found to be in positive linear correlation with the applied laser energy.