Doping behavior of phosphorus in ZnO thin films: Effects of doping concentration and postgrowth thermal annealing

Abstract

Effects of phosphorus concentration, [P], and postgrowth annealing on the x-ray diffraction and Raman scattering from ZnO:P thin films are presented. The ZnO (0002) diffraction peak exhibits a large monotonic angular shift with increasing [P] up to 5.1× 1019 cm-3 while its shift upon annealing is dependent on [P]. No extrinsic phases were detected for the samples studied. Raman spectra reveal disorder-activated vibrational modes, around 276, 510, 582, and 643 cm-1, with increasing [P]. They also reveal local vibrational modes corresponding to PO (∼370 cm -1) and PZn (∼482 cm-1) upon annealing. The intensity evolution of the Raman features, together with the x-ray diffraction results, indicates that phosphorus substituting for zinc is favored at low annealing temperatures while increasing annealing temperature tends to convert phosphorus doping configurations from PZn to PO. © 2010 American Institute of Physics.