| 1. |
- Lefez, B., et al.
(författare)
-
Application of reflectance spectrophotometry to the study of copper (I) oxides (Cu2O and Cu3O2) on metallic substrate
- 1994
-
Ingår i: Surface and Interface Analysis. - : Wiley. - 0142-2421 .- 1096-9918. ; 22:1-12, s. 451-455
-
Tidskriftsartikel (refereegranskat)abstract
- The aim of this study is to characterize the compounds grown on copper during the oxidation at low temperature (T < 523 K) by optical methods: photoluminescence and UV‐Visible‐NIR diffuse reflectance spectroscopy. Two cuprous oxides Cu2O and Cu3O2 have been studied. The absorption of Cu2O films in the range 450–630 nm is mainly due to non‐stoichiometry bands associated with copper and oxygen vacancies. Cu3O2 is characterized by an optical band gap greater than that of Cu2O (respectively 2.25 and 1.95 eV) and by an intense luminescence emission at 760–780 nm. Cu3O2 may be considered as a gross defect structure of Cu2O (a Cu 2O = 0.427 nm, a Cu 3O 2 = 0.431 nm). The experimental approach of the oxidation mechanism reveals that at 423 K Cu2O is the primary product which later on is transformed into Cu3O2. Experimental and calculated optical absorption curves disclose the nucleation of CuO inside the cuprous oxides layer for oxidation in the range 473–523 K.
|
|
| 2. |
- Roos, A., et al.
(författare)
-
Diffuse reflectance and transmittance spectra of an interference layer : 1. Model formulation and properties
- 1994
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 33:34, s. 7908-7917
-
Tidskriftsartikel (refereegranskat)abstract
- A model for the calculation of the diffuse reflectance and transmittance of a single interference layer with rough interfaces on a transparent substrate is presented. The model is based on electric field calculations and scalar scattering theory, and it assumes that the interfaces of the layer are totally uncorrelated. Examples are given of calculated spectra in which the parameters of the model are varied systematically to show the influence from different interface roughness and refractive index combinations as well as absorption in the film. A wavelength-dependent effective root-mean-square roughness is introduced. This depends on the nature of the roughness, and the bandwidth limits are given by the experimental conditions. Finally, total integrated scattering spectra are calculated and the importance of taking multiple reflections in the substrate into account is shown.
|
|
| 3. |
- Rönnow, Daniel, et al.
(författare)
-
Design review of an instrument for spectroscopic total integrated light scattering measurements in the visible wavelength region
- 1994
-
Ingår i: Review of Scientific Instruments. - : AIP Publishing. - 0034-6748 .- 1089-7623. ; 65:2, s. 327-334
-
Tidskriftsartikel (refereegranskat)abstract
- A spectroscopic total integrated scattering instrument, which uses a focusing sphere and a broadband light source, has been constructed. It records total reflectance and transmittance spectroscopically, in the wavelength region 400-1000 nm. Diffuse reflectance and transmittance values below 10-4 can be registered. These measurements require low scattering optical components and low noise electronics. Design details are given about the detection system, particularly the low noise preamplifier. The purpose of the instrument is to measure diffuse reflectance and transmittance spectra of interference coatings. Such spectra can give information about the amplitude of the roughness of the interfaces and reveal if the interfaces are topographically correlated or uncorrelated. Examples of spectra in both reflectance and transmittance mode are given.
|
|
| 4. |
- Rönnow, Daniel, et al.
(författare)
-
Determination of interface roughness by using a spectroscopic total-integrated-scatter instrument
- 1993
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 32:19, s. 3448-3451
-
Tidskriftsartikel (refereegranskat)abstract
- A spectroscopic total-integrated-scatter instrument has been constructed. It uses a Coblentz sphere for the collection of the scattered light and a lamp with a monochromator as a light source. It can be used to measure diffuse reflectance as well as transmittance. The instrument has been used to measure diffuse reflectance of thermally and chemical-vapor-deposition oxidized silicon wafers. Comparisons are made with measurements by using a spectrophotometer with an integrating sphere. The data have been interpreted with a parameterized model for light scattering from a double layer, to obtain rms surface roughness values for the two interfaces of the oxide film.
|
|
| 5. |
- Rönnow, Daniel, et al.
(författare)
-
Diffuse reflectance and transmittance spectra of an interference layer. 2. Evaluation of tin oxide-coated glass
- 1994
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 33:34, s. 7918-7927
-
Tidskriftsartikel (refereegranskat)abstract
- A model for the calculation of diffuse reflectance and transmittance of a single interference layer on a transparent substrate is applied to pyrolytically deposited tin oxide films on glass. Total as well as diffuse reflectance and transmittance spectra were measured in an integrating sphere, and scattering levels between 0.002 and 0.1 were recorded. The optical constants and the thickness of the films were determined from the total reflectance and transmittance spectra. The wavelength-dependent effectiveroot-mean-square roughness of aluminum-coated tin oxide front surfaces was determined by the application of the scalar scattering theory. Surface roughness values between 5 and 25 nm were obtained. The obtained effective rms roughness values of the air-film interface were used together with the other film parameters to calculate the diffuse reflectance and transmittance spectra of the tinoxide-coated glass substrates. A comparison between calculated and experimental spectra showed good agreement for diffuse reflectance, diffuse transmittance, and total integrated scattering spectra.
|
|
| 6. |
- Rönnow, Daniel, et al.
(författare)
-
Stray-light corrections in integrating-sphere measurements on low-scattering samples
- 1994
-
Ingår i: Applied Optics. - 1559-128X .- 2155-3165. ; 33:25, s. 6092-6097
-
Tidskriftsartikel (refereegranskat)abstract
- A method for correcting integrating-sphere signals that considers differences in the angular distribution of scattered light is extended to sources of errors that are due to stray light from imperfect optical components. We show that it is possible to measure low levels of scattering, below 1%, by using a standard integrating sphere, provided that the various contributions to stray light are taken into account properly. For low-scattering samples these corrections are more important than those from the angular distribution of the scattering. A procedure for the experimental determination of stray-light components is suggested. Simple, easy to use, compact equations for the diffuse and specular reflectance and transmittance values of the sample as functions of the recorded signals are presented.
|
|
