Surface morphology, compositions, microstructure and optical properties of GaN film irradiated by highly charged Kr^(q+)(q = 23, 15, 11) in two geometries to a fluence of 1×10^(15)kr^(q+)/cm^2 were studied using ...Surface morphology, compositions, microstructure and optical properties of GaN film irradiated by highly charged Kr^(q+)(q = 23, 15, 11) in two geometries to a fluence of 1×10^(15)kr^(q+)/cm^2 were studied using AFM,XPS, PL, Raman scattering and UV–visible spectroscopy.The AFM observation shows that the irradiated GaN area is a swollen terrace. The swelling rate increased with the charge state(potential energy). For the same charge state,the swelling rate of tilted incidence was greater than that for normal incidence. The XPS measurements reveal that N deficiency, Ga enrichment and Ga–O and Ga dangling bonds generated on the irradiated GaN surface increased with the charge state, and more N was lost for normal incidence than that for tilted incidence. The UV–Vis results show that the transmittance decreased with increasing charge state. For the same charge state, the transmittance for tilted incidence is higher than that for normal incidence.The PL spectra present that, with increasing charge state,the YL band intensity decreased, with a blueshift in its peak position; while the NBE peak intensity increased firstand then reduced, and a blue luminescence band appeared.A rapid quenching of both the YL and the NEB for normal incidence was observed. Raman spectra display that screw dislocations perhaps were produced near the surface for normal incidence.展开更多
基金supported by the National Natural Science Foundation of China(Nos.11675231,91426304 and 11105191)the National Magnetic Confinement Fusion Program(No.2011GB108003)the National Basic Research Program of China(No.2010CB832904)
文摘Surface morphology, compositions, microstructure and optical properties of GaN film irradiated by highly charged Kr^(q+)(q = 23, 15, 11) in two geometries to a fluence of 1×10^(15)kr^(q+)/cm^2 were studied using AFM,XPS, PL, Raman scattering and UV–visible spectroscopy.The AFM observation shows that the irradiated GaN area is a swollen terrace. The swelling rate increased with the charge state(potential energy). For the same charge state,the swelling rate of tilted incidence was greater than that for normal incidence. The XPS measurements reveal that N deficiency, Ga enrichment and Ga–O and Ga dangling bonds generated on the irradiated GaN surface increased with the charge state, and more N was lost for normal incidence than that for tilted incidence. The UV–Vis results show that the transmittance decreased with increasing charge state. For the same charge state, the transmittance for tilted incidence is higher than that for normal incidence.The PL spectra present that, with increasing charge state,the YL band intensity decreased, with a blueshift in its peak position; while the NBE peak intensity increased firstand then reduced, and a blue luminescence band appeared.A rapid quenching of both the YL and the NEB for normal incidence was observed. Raman spectra display that screw dislocations perhaps were produced near the surface for normal incidence.
