  Defect engineering using self-doping or creating vacancies in polycrystalline
oxide based materials has profound influence on optical absorption, UV photo
detection, and electrical switching. However, defects induced semiconducting
oxide devices show enhancement in photo detection and photosensitivity, and
hence still remain interesting in the field of optoelectronics. In this study,
defect engineering in semiconducting oxide materials is discussed along with
their roles in optoelectronic device-based applications. Theoretical
investigations have been done for identifying defect states by performing
first-principles electronic structure calculations, employing the
density-functional theory. Particularly, in this work, we have focused on
probing the defect-induced changes in optical and electrical processes by means
of experimental as well as computational investigations. Hence, systematic
experimental measurements of optical absorption, electrical switching, charge
density, and photocurrent in defect-rich semiconducting oxide samples have been
performed. Our results suggest that defects can lead to enhancement of
optoelectronic properties such as photocurrent, switching speed, optical
absorption, etc. for semiconducting oxide based devices.
