An Investigation of the optoelectrical properties of n-TiO2Eu/p-Si heterojunction photodiode

Abstract

In the present investigation, titanium dioxide (TiO2) and Euphorium (Eu) doped TiO2 films were deposited on both glass and n-Si substrates via employing sol-gel spin coating technique to characterize optical, morphological, chemical features and scrutinize their heterojunction applications. The atomic force microscope (AFM), Ultraviolet-visible (UV-VIS) and Raman studies were conducted to inspect the morphological, optical, chemical, and crystal phase properties of thin films, respectively. The optical band gap of TiO2 films widened from 3.40 eV to 3.44 eV with increasing Eu doping concentration. The Raman analyses displayed that the deposited TiO2 films were in the anatase phase. The AFM images indicated Eu substitution influences the surface structure of the fabricated films. The optoelectrical properties of the fabricated heterojunction structures were determined under dark and various illumination intensities. When the optoelectrical properties of the obtained diodes were examined, it was realized that while the ideality factor (η) and series resistance (RS) decreased, the barrier height (ΦB), photosensitivity and photoresponse parameters increased with the optimum Eu concentration. The results underscore that Eu substitution into TiO2 structure influences structural, optical, and electrical parameters. Thus, the Eu material could be used as a potential candidate to improve the optoelectrical performance of n-TiO2/p-Si.