Room temperature optical and magnetic properties of (Cu, K) doped ZnO based diluted magnetic semiconductor thin films grown by chemical bath deposition method

• Novel (K, Cu)-doped ZnO thin films were grown by CBD technique.
• Typical room temperature ferromagnetism was exhibited by the thin films.
• Decrease in band gap with increase in copper concentrations.
• This film are ferromagnetic semiconductor.
• This films are suitable for spintronics applications.

ZnO based diluted magnetic semiconductor thin films were prepared by simultaneously doping the non-magnetic Cu and K in the cation sites of the host ZnO employing the chemical bath deposition method. In this study, K was kept at a concentration of 1% and Cu concentration was varied at 1%, 2%, 3% and 4%. For comparative study, 1% K doped ZnO was also prepared. The influence of K and Cu doping on the transmittance, band gap and magnetic properties were investigated. The XRD revealed that the thin films are polycrystalline and has hexagonal wurtzite crystal structure of ZnO without any secondary phases. Well developed hexagonal structures are observed from the surface morphology. The transmittance shows a significant variation when Cu is incorporated at different doping levels along with K and the band gap change is significant for higher concentration. The room temperature magnetic hysteresis revealed the typical ferromagnetic behavior of K doped and (K, Cu) doped ZnO thin films. The K and Cu doped ZnO thin film exhibited enhanced magnetization compared to K doped ZnO thin film. The present study reveals that the magnetic results of the K and Cu doped ZnO are markedly better than that of the Cu doped ZnO reported by other experiments. The magnetic properties have been explained on the basis of the photoluminescence spectrum. The origin of ferromagnetism is due to the p–d hybridization which has the influence on the band gap also.