Micro-x-ray Absorption Structure (XAS) of Oxidized Ni/Au Contacts to p-GaN
Studies by Photoelectron Emission Microscopy (PEEM)
J. C. Jan (詹智全)1, J. W. Chiou (邱昭文)1, W. F. Pong (彭維鋒)1,
D. H. Wei (魏德新)2, Y. J. Hsu (許瑤真)2, G. C. Yin (殷廣鈐)2, Y. S. Wu (吳燿杉)2,
L. C. Chen (陳立千)3, F. R. Chen (陳福隆)3
1)
Department of Physics, Tamkang University, Tamsui 251, Taiwan.
2)
Synchrotron Radiation Research Center, Hsinchu 300, Taiwan
3)
Department of Engineering System Science, National Tsing Hua University, Hsinchu 300,
Taiwan.
Normalized Absorption (arb. units)
We have used the photoelectron emission microscopy (PEEM) to study electronic structure
of as-deposited and oxidized Ni/Au contacts to p-GaN samples. Fig. 1(a) and (b) show the image
and micro-XAS in area A of As-deposited p-GaN/Ni(100Å)/Au(50Å) sample at photon energy hv=
849eV, respectively. The spectrum of as-deposited clearly is similar that of Ni metal, shown in the
inset of Fig. 1(b). Fig. 2(a) shows the image of p-GaN/Ni(100Å)/Au(50Å), which was annealed in
air at 500oC. The micro-XAS spectra of area B and C shown in Fig. 2(b) are close to that of NiO as
shown in the inset of figure. The result of x-ray absorption near edge structure (XANES) will be
also presented.
Ni L3,2-edge
(b)
Ni-metal
850
860
870
Area A
850
860
870
Photon Energy(eV)
Normalized Absorption (arb. units)
Fig.1 The image (a) and micro-XAS spectrum (b) of as-deposited p-GaN/Ni(100Å)/Au(50Å) sample
Ni L3,2-edge
(b)
NiO-Film
850
860
870
Area B
Area C
850
860
870
Photon Energy (eV)
Fig.2 The image (a) and micro-XAS spectrum (b) of annealing p-GaN/Ni(100Å)/Au(50Å) sample.