Valence Band and Conduction Band Offset Between 3% and 7% Ni Doped Znnio and Zno Heterointerfaces

Structural, optical, and electronic properties of PLD grown Zn 1-x Ni x O/ZnO thin films have been studied by grazing angle XRD (Gi-XRD), UV-visible spectroscopy, x-ray photoelectron spectroscopy, and valance band spectroscopy. Gi-XRD analysis revealed that all Ni ions in the deposited thin films have been completely occupied within the ZnO lattice and the wurtzite symmetry is also retained as it in ZnNiO/ZnO bilayers. The bandgap of doped thins films decreases with increasing Ni concentration due to the collective effect of sp-d interaction, Burstein-Moss (BM) effect, and tensile stress reduction. Type-II band alignment (staggered gap) has been observed in ZnNiO/ZnO hetero-interface with conduction band and valence band offset values of -0.06 eV and 0.15 eV respectively for Ni-2p state, -0.22 eV and 0.31 eV respectively for Zn-2p state for 3% of Ni doping. For 7% of Ni doping conduction and valance band offsets of -0.17 eV and 0.31 eV respectively has been obtained for Ni-2p state, -0.29 eV and 0.43 eV respectively for Zn-2p state. The precise calculation of band offsets in ZnNiO/ZnO for both Ni-2p and Zn-2p core energy levels and band-gap values will be very helpful in designing and fabricating optoelectronic devices like LEDs, photodetectors, etc.