Materials for solar thermal conversion. Quarterly report No. 1, September 1--December 31, 1977. [Ge--CaF/sub 2/ and Si--CaF/sub 2/ composites]

Technical Report · Sun Jan 01 00:00:00 EST 1978

DOI:https://doi.org/10.2172/6049538· OSTI ID:6049538

Gittleman, T. I.

Specimens of Ge--CaF/sub 2/ and Si--CaF/sub 2/ composites have been prepared for: (1) the determination of the optical constants; (2) the characterization of the composite semiconductors; and (3) reflectance measurements (when specimens were deposited on mirror substrates). While the results of Auger, ESCA and TEM analyses are not yet available, a picture of the composite semiconductors is beginning to emerge based on the wavelength dependence of the optical constants. As noted in the previous section ..cap alpha.. = A(h..nu..--E/sub 0/)/sup 2/ where A increases as f/sub v/ increases and E/sub 0/ is independent of f/sub v/. Thus, the semiconductor composites behave like semiconductors with an energy gap equal to that of the semiconductor component and with a reduced index of refraction. The above property is just the one needed for efficient selective absorption. This is demonstrated by the reflectance of the composite films on mirrors. The reflectance measurements also reveal unexpected absorption bands which may be due to chemical reaction between the semiconductors and the insulator. When the source of this absorption is determined, methods of eliminating it will be explored.

• Research Organization: RCA Labs., Princeton, NJ (USA)
• DOE Contract Number: EG-77-C-02-4557
• OSTI ID: 6049538
• Report Number(s): TID-28787
• Country of Publication: United States
• Language: English

Related Subjects

14 SOLAR ENERGY
CALCIUM FLUORIDES
CHEMICAL COMPOSITION
CHEMICAL PREPARATION
GERMANIUM
SILICON
SOLAR ABSORBERS
SPECTRALLY SELECTIVE SURFACES
ABSORPTIVITY
ANNEALING
AUGER ELECTRON SPECTROSCOPY
COMPOSITE MATERIALS
ELECTRON MICROSCOPY
OPTICAL PROPERTIES
REFLECTIVITY
SEMICONDUCTOR MATERIALS
ALKALINE EARTH METAL COMPOUNDS
CALCIUM COMPOUNDS
CALCIUM HALIDES
ELECTRON SPECTROSCOPY
ELEMENTS
FLUORIDES
FLUORINE COMPOUNDS
HALIDES
HALOGEN COMPOUNDS
HEAT TREATMENTS
METALS
MICROSCOPY
PHYSICAL PROPERTIES
SEMIMETALS
SPECTROSCOPY
SURFACE PROPERTIES
SURFACES
SYNTHESIS
141000* - Solar Collectors & Concentrators