Bi₂O₃ nanosheets- based photodetectors designed for visible light communication technology

Abstract In this work, n-type bismuth oxide nanosheets deposited onto n-type silicon substrates by a vacuum evaporation technique under a vacuum pressure of 10 −5 mbar is fabricated to perform as a daylight photodetectors suitable for visible light and infrared communication technology. The n-Si/n-Bi 2 O 3 heterojunction devices exhibited conduction and valence band offsets of 0.89 eV 0.73 eV, respectively. Two Schottky barriers Pt/n-Si and Pt/Bi 2 O 3 of respective barrier heights of 1.65 eV and 0.76 eV are formed on the sides of the heterojunction devices. Dark electrical characterization on the Pt/n-Si/n-Bi 2 O 3 /Pt hybrid structure showed a maximum current rectification ratio of 166. The current transport mechanism in the devices was dominated by the Richardson –Schottky thermionic conduction type and by electric field assisted charge carrier tunneling within a barrier of width and height of 60 nm and 0.83 eV, respectively. On the other hand, electrical measurements handled under the illumination of a daylight mini-lamp have shown that the photodetectors under focus exhibit maximum current responsivity, external quantum efficiency percentage, specific detectivity and linear dynamic range of 30 A W −1 , 3000%, 1.7 <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>12</mml:mn> </mml:mrow> </mml:msup> </mml:math> Jones and 36.4 dB under illumination power of 82 μW, respectively. The features of the bismuth oxide based photodetectors nominate them for visible and infrared lights illumination technology.