Abstract: Phosphorus was diffused into CVT grown undoped ZnO bulk single crystals at 550 and 800℃ in a closed quartz tube.The P-diffused ZnO single crystals were characterized by the Hall effect,X-ray photoelectron spectroscopy (XPS),photoluminescence spectroscopy (PL),and Raman scattering.The P-diffused ZnO single crystals are n-type and have higher free electron concentration than undoped ZnO,especially for the sample diffused at 800℃.The PL measurement reveals defect related visible broad emissions in the range of 420~550nm in the P-diffused ZnO samples.The XPS result suggests that most of the P atoms substitute in the Zn site after they diffuse into the ZnO single crystal at 550℃,while the P atom seems to occupy the O site in the ZnO samples diffused at 800℃.A high concentration of shallow donor defect forms in the P-diffused ZnO,resulting in an apparent increase of free electron concentration.

Key words: diffusion, defect, ZnO, phosphorus