Sm doped Co3O4: Development of a low-cost high-performance photodetector for optoelectronic devices

Abstract

Undoped and Sm doped cobalt oxide (Co3O4) thin films were successfully deposited onto bare glass substrates using a nebulizer spray technique. The Sm weight concentration varied from 1 % to 4 %. To investigate the effects of doping on the crystal shape, structure, emission, and light absorption characteristics of the deposited Co3O4 films, an analysis employing various analytical techniques was carried out. The electrical properties of the thin films are studied utilizing a Keithley source meter. All of the developed Co3O4 films reveal a cubic spinel structure. Nanocrystalline grains and some overgrown clusters are seen in the Co3O4 morphology and were found to vary with the concentration of Sm (1, 2, 3, and 4 wt%). With a rise in the number of Sm dopants in the Co3O4 films, the mean grain size is observed to increase as observed through FESEM images. The energy-dispersive X-ray examination of the Co3O4:Sm 3 % sample confirms the presence of Co, O, and Sm elements. The 3 % Sm-doped Co3O4 thin film exhibits a greater absorption value and a lower transmittance, according to the optical studies. Additionally, it was revealed that the optical band gap value decreases from 2.23 to 2.11 eV and 1.48–1.45 eV as Sm doping concentration was increased from 0 % to 3 %. The 3 % Sm doped Co3O4 thin film sample reveals a maximum photocurrent of 9.32 × 10−5A. Thus it is established that the addition of Sm doping to Co3O4 increases its photo detecting capabilities, making it a favorable option for use in photo-detectors.