Improved photovoltaic effect in CuO/Zn1−xMgxO heterojunction solar cell by pulsed laser deposition

In this study, the effect of Mg content in CuO/Zn1−xMgxO heterojunction thin films have been systematically investigated. This heterojunction was fabricated by Pulsed laser deposition on indium tin oxide-covered glass substrate for solar application. The structural and optical properties of this heterostructure were analyzed by x-ray diffraction and ultraviolet-visible spectroscopy. The optical measurements reveal a shift in absorption edge and increase in transmittance with Mg content. Tuning of the band gap has been obtained from 3.28 to 3.5 eV corresponding to Mg content x varies from 0 to 0.10. An enhancement of open circuit voltage (Voc) from 178 to 326 mV and short circuit current density (Jsc) from 2.06 to 2.13 mA/cm2 with the increase of Mg content was observed. It may be due to the conduction band of this heterojunction (CuO/Zn1−xMgxO) moving closer to vacuum level with increasing x. The maximum solar power conversion efficiency (ɳ=0.253%) was found with x=0.10. Hence, this improved solar power conversion efficiency in CuO/Zn1−xMgxO heterojunction makes this promising candidate for photovoltaic application.