Optical band gap tuning of Sb-Se thin films for xerographic based applications

• Amorphous SbxSe100-x (x = 0, 5, 20, 50 and 60) thin films are highly transparent in near IR-region.
• Transmittance decreases with Sb addition due to increase in localized states.
• Optical band gap decreases with Sb addition.
• Decrease in optical band gap of thin films has been explained using chemical bond approach and density of states model.

In the present paper we have studied the effect of Sb addition on the optical band gap tuning of thermally evaporated SbxSe100-x (x = 0, 5, 20, 50 and 60) thin films. The structural investigations revealed that all thin films were amorphous in nature. Transmission spectrum was taken in the range 400–2500 nm shows that all films are highly transparent in the near infrared region. The fundamental absorption edge shifts towards longer wavelength with Sb incorporation. The optical band gap decreases with addition of antimony in a-Se thin films. A good correlation has been drawn between experimentally estimated and theoretically calculated optical band gap. The decrease in optical band gap of thin films has been explained using chemical bond approach and density of states model. Decrease in optical band gap with Sb addition increases the concentration of electron deep traps which increases the X-ray sensitivity of Sb-Se thin films. Thus by tuning the optical band gap of Sb-Se alloy, it could be utilized for xerographic based applications.