Browsing by Author "Pei, JH"

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Characterization of CdTe film grown on a Si(111) substrate
(1998-02-01)
Pei, JH
;
Lin, CM
;
Chuu, DS
;
電子物理學系
;
物理研究所
We report the characterization of polycrystalline CdTe films grown on Si(111) by using UHV sublimination techniques. Films grown at substrate temperature below 250 degrees C exhibited streaked X-ray diffraction patterns. To understand the native oxide on the film surface, the films were exposed to a laboratory air environment in the growth chamber for several days. The XPS spectra were taken after each Ar-ion sputtering of these oxidized films. In order to obtain more information from the measured XPS data, we performed core-level line-shape analysis. Based on previously reported studies, CdTe, TeO2, and element Te are constituents in the film, while Cd is almost all in the CdTe state. Raman scattering from oxidized CdTe film in the frequency of 550-900 cm(-1) reveals that TeO2 is the predominant oxide.
Characterization of CdTe film grown on a Si(111) substrate
(1998-02-01)
Pei, JH
;
Lin, CM
;
Chuu, DS
;
電子物理學系
;
物理研究所
We report the characterization of polycrystalline CdTe films grown on Si(111) by using UHV sublimination techniques. Films grown at substrate temperature below 250 degrees C exhibited streaked X-ray diffraction patterns. To understand the native oxide on the film surface, the films were exposed to a laboratory air environment in the growth chamber for several days. The XPS spectra were taken after each Ar-ion sputtering of these oxidized films. In order to obtain more information from the measured XPS data, we performed core-level line-shape analysis. Based on previously reported studies, CdTe, TeO2, and element Te are constituents in the film, while Cd is almost all in the CdTe state. Raman scattering from oxidized CdTe film in the frequency of 550-900 cm(-1) reveals that TeO2 is the predominant oxide.
High-pressure phase transitions in Zn1-xMxSe (M=Cd, Fe, and Mn)
(1998-07-01)
Lin, CM
;
Chuu, DS
;
Xu, JA
;
Huang, E
;
Chou, WC
Energy-dispersive x-ray diffraction was employed to study pressure-induced phase transitions in Zn0.84Fe0.16Se, Zn0.9Cd0.1Se, and Zn0.76Mn0.24Se crystals up to 21.0, 23.3, and 24.3 GPa, respectively. Our result shows that the B3 to B1 structure transitions for these crystals occurred at 1 1.4 +/- 0.5, 9.5 +/- 0.3, and 9.6 +/- 0.5 GPa, respectively. Compared to the phase-transition pressure (P-t) of ZnSe (14.4 GPa), a reduction of about 3-5 GPa is exhibited in these ternary compounds. This reduction in phase-transition pressure Delta P-t in the ternary compounds suggests that the fractional volume change, (Delta V/V-o), of the B3-B1 phase admixture might be the source of this reduction. Our results indicate that P-t (with respect to the phase transition pressure 14.4 GPa of ZnSe) is related to the fractional volume change (Delta V/V-o) by the expression P-t = [14.4003 + 0.1568 (Delta V/V-o)-0.0281(Delta V/V-o)(2)] GPa. [S0163-1829(98)05426-5].
Phase transitions of Zn0.84Fe0.16Se under high-pressure
(1998)
Lin, CM
;
Chuu, DS
;
Chou, WC
;
Xu, JA
;
Huang, E
The energy-dispersive X-ray-diffraction (EDXD) and Raman spectroscopy were employed to study the pressure induced phase transitions of Zn0.84Fe0.16Se crystal up to 21.0 and 32.0 GPa, respectively. A semiconductor-metal transition was identified by EDXD and Raman spectroscopic methods at 11.4 +/- 0.5 GPa. Other two phase transitions were found only in the Raman scattering study below 11.4 GPa. In addition, three unidentified Raman peaks were still observable above the metallization pressure. The existence of Fe impurity in the ZnSe up to a concentration of 0.16 reduced prominently the semiconductor-metal phase transition pressure. For Raman works, the three unidentified Raman peaks of Zn0.84Fe0.16Se above 10.9 GPa are possibly the TO modes in the thin surface of the high pressure metallic phase. (C) 1998 Elsevier Science Ltd. All rights reserved.