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Ex. 1: Reflectance spectra collected over 190–1000nm wavelength range for an amorphous silicon film (a-Si) on an oxidized silicon substrate (SiO 2 /Si-Sub) plus the n(λ) and k(λ) spectra of the a-Si film. The film thickness was found to be 1147nm.
If R 1 represents a clean freshly prepared surface (e.g., after a cleavage in vacuum) and R 2 the same sample after the exposure to hydrogen or oxygen contaminants, the ΔR/R spectrum can be related to features of the clean surface (e.g., surface states); [2] if R 1 is the reflectivity spectrum of a sample covered by an organic film (even if ...
For layered and finite media, according to the CIE, [citation needed] reflectivity is distinguished from reflectance by the fact that reflectivity is a value that applies to thick reflecting objects. [6] When reflection occurs from thin layers of material, internal reflection effects can cause the reflectance to vary with surface thickness.
Refraction at interface. Many materials have a well-characterized refractive index, but these indices often depend strongly upon the frequency of light, causing optical dispersion.
Photo-reflectance has been particularly important in basic research on semiconductors due to its ability to precisely determine semiconductor bandstructures (even at room temperature). As an optical technique, photo-reflectance would appear suited to industrial applications because it is non-contact, and because it has good spatial resolution.
Attenuated total reflection (ATR) is a sampling technique used in conjunction with infrared spectroscopy which enables samples to be examined directly in the solid or liquid state without further preparation. [1] Light undergoes multiple internal reflections in the crystal of high refractive index, shown in yellow.
The term "spectroscopic" relates to the fact that the information gained is a function of the light's wavelength or energy (spectra). The technique has been known at least since 1888 by the work of Paul Drude [1] and has many applications today. The first documented use of the term "ellipsometry" was in 1945. [2] [non-primary source needed]
A graph showing variation of internal quantum efficiency, external quantum efficiency, and reflectance with wavelength of a crystalline silicon solar cell. A solar cell's quantum efficiency value indicates the amount of current that the cell will produce when irradiated by photons of a particular wavelength.