Abstract
Undoped and antimony (Sb) doped ZnO films were synthesized on sapphire (0001) substrates using Pulsed Laser Deposition (PLD) method. Structural and morphological studies proved the good crystallinity of the ZnO films with c-axis (0002) orientation growth. The substitution of Sb in ZnO lattice was proved from the analysis of XPS data. Interestingly, it was important that the presence of Sb5+ ions opened the way for the apparition of the complex acceptor (SbZn–2VZn) level with high stability. The decrease in the value of the band gap Eg with Sb doping evidenced the creation of energy levels related to such complex acceptor. From the study of photoluminescence (PL) at low temperatures, it was shown the dominant emission is related to free electron transition from neutral acceptor (e, A0), indicating the conductivity conversion from n to p with Sb doping. The reproducibility and stability of p-type conduction from the ZnO:Sb3% films were evaluated by Hall measurements. As application, ZnO homojunction device was carefully made and shows rectifying current-voltage (I–V) characteristics, typical to perfect diode. Thus, the prepared ZnO–Sb films are promising for application in optoelectronic field.
•Epitaxial ZnO–Sb films were grown on (0001) sapphire by advanced PLD way.•PL measurements at low temperatures revealed the formation of acceptors levels.•Reproducible and stable p-type conductivity of ZnO–Sb3% was evaluated for optoelectronic application.•ZnO homojunction device with good characteristics for potential LED application is demonstrated.