Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te studied by variable angle spectroscopic ellipsometry between 0.75 and 6.24 eV

Conference · Fri Jan 07 04:00:00 EST 2000

OSTI ID:755814

James, Ralph B

Optical properties of Cd{sub 0.9}Zn{sub 0.1}Te (CZT) were studied by variable angle spectroscopic ellipsometry (VASE). Measurements made by VASE were performed on CZT and CdTe samples in air at room temperature at multiple angles of incidence. A parametric function model was employed in the VASE analysis to determine the dielectric functions {var_epsilon}={var_epsilon}{sub 1} + i{var_epsilon}{sub 2} in the range of 0.75 to 6.24 eV. A two-oscillator analytical model was used to describe the dielectric response of native oxides on CZT. Surface oxide optical properties and thickness on CZT were also determined in conjunction with the VASE measurement and analysis of a CdTe sample. Two samples of CZT of different oxide thicknesses were measured and their optical constants were coupled together in a multiple-sample, multiple-model VASE analysis to resolve correlations between fitting parameters. Effective medium approximation (EMA) was used to describe the optical properties of the CZT oxide with roughness. A Kramers-Kronig self-consistency check of the real and imaginary parts of the Cd{sub 0.9}Zn{sub 0.1} dielectric functions was performed over the energy range 0.75 to 6.24 eV. A five-Lorentz-oscillator model was employed to describe the dielectric response of CZT in the range of 1.6 to 6.24 eV. Intensity transmission measurements were made on the Cd{sub 0.9}Zn{sub 0.1}Te and CdTe, showing the absorption energy band edges of {approximately} 1.58 and 1.46 eV, respectively.

• Research Organization: Sandia National Labs., Albuquerque, NM (US); Sandia National Labs., Livermore, CA (US)
• Sponsoring Organization: US Department of Energy (US)
• DOE Contract Number: AC04-94AL85000
• OSTI ID: 755814
• Report Number(s): SAND2000-8524C
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY
CADMIUM TELLURIDES
DATA ANALYSIS
DIELECTRIC PROPERTIES
ENERGY SPECTRA
GAMMA DETECTION
OPTICAL PROPERTIES
PERFORMANCE
RADIATION DETECTORS
X-RAY DETECTION
ZINC TELLURIDES