Novel Technique for Improving the Signal-to-Background Ratio of X-ray Absorption Near-Edge Structure Spectrum in Fluorescence Mode and Its Application to the Chemical State Analysis of Magnesium Doped in GaN

A novel measurement technique for an X-ray absorption near-edge structure (XANES) for magnesium (Mg) doped in gallium nitride (GaN) has been developed. XANES spectra from Mg at very low concentrations of $1 \times 10^{18}$/cm 3 doped in GaN have successfully been obtained by optimizing the region of...

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Published inJapanese Journal of Applied Physics Vol. 52; no. 12; pp. 126602 - 126602-4
Main Authors Yonemura, Takumi, Iihara, Junji, Saito, Yoshihiro, Ueno, Masaki
Format Journal Article
LanguageEnglish
Published The Japan Society of Applied Physics 01.12.2013
Subjects
Annealing
Atomic structure
Gallium nitrides
Magnesium
Optimization
Spectra
Synchrotron radiation
X-ray fluorescence
X-rays
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Summary:A novel measurement technique for an X-ray absorption near-edge structure (XANES) for magnesium (Mg) doped in gallium nitride (GaN) has been developed. XANES spectra from Mg at very low concentrations of $1 \times 10^{18}$/cm 3 doped in GaN have successfully been obtained by optimizing the region of interest (ROI) and by using highly brilliant synchrotron radiation X-rays of SPring-8. The ROI is the limited energy region from an X-ray fluorescence spectrum to elicit signals of particular atoms. Using this new technique, we have investigated the effect of the annealing process for Mg-doped GaN on the XANES spectra. It has been found that the XANES spectra of Mg significantly changed as the annealing temperature increased. This indicates that the local structure around Mg atoms in GaN was modified by the annealing process.
Bibliography:Model of BG interference of the target fluorescence peak from the neighboring peak. The broken square with diagonal lines indicates the ROI for XANES measurements in the fluorescence mode. ROI dependence of $f_{\text{target}}$, $f_{\text{BG}}$, and $f_{\text{target}}/f_{\text{BG}}$ when $S_{\text{target}}/S_{\text{BG}}$ is set to 1.00. (Color online) Schematic diagram of measurement system. Fluorescence spectra of samples A and B1 at an excitation energy of 1320 eV. Intensities in the vertical axis are normalized with the peak intensity of each sample. Mg K-XANES spectra of sample B1 at various ROIs. The Mg K-XANES spectrum of sample A is superimposed. The lower limit of ROIs in XANES spectra of sample B1 is changed from the 450th channel to the 500th channel at intervals of 10 channels. The upper limit of ROI is located at the 550th channel. Mg K-XANES spectra of samples B2 and A. Two spectra are observed for sample B2 with two lower limits of 450th and 500th channels. The upper limit of ROI is located at the 550th channel. Mg K-XANES spectra of Mg-doped GaN and samples C1, C2, and C3. Sample C1 is not annealed and samples C2 and C3 are annealed at 500 and 800 °C, respectively.
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ISSN:0021-4922
1347-4065
DOI:10.7567/JJAP.52.126602