Role of Pzn-2Vzn centre on the luminescence properties of phosphorus doped ZnO thin films by varying doping concentration

Zinc oxide (ZnO) thin films were deposited using RF sputtering followed by plasma immersion ion implantation for 10-70 s to dope phosphorus on ZnO. Optical and structural characteristics from particular experiments (Photoluminescence (PL)), High resolution X-ray diffraction (HRXRD) and energy dispersive x-ray spectroscopy (EDX) confirms presence of phosphorus doping in implanted ZnO thin films. Dominant peak at around 3.35 eV measured from low temperature PL (18 K) measurement which assign as neutral acceptor-bound exciton peak. Two peaks: free electron acceptor and donor bound acceptor were observed at around 3.32 and 3.25 eV. The acceptor level was observed at 107 meV above the valence band. All samples exhibited dominant (002) crystal orientation peak in HRXRD measurements, indicating perfect c-axis orientation. Highest carrier (hole) concentration of 9.94 × 1017 cm−3 was measured from 60 s implanted sample. Formation of complex acceptor PZn-2VZn was justified by EDX measurements.