W. D. Lawson, Steen Brøndsted Nielsen, E H Putley et al.|Journal of Physics and Chemistry of Solids|1959
Cited by 388
Electronics and Radar Development Establishment
Publishes on Advanced Semiconductor Detectors and Materials, Chalcogenide Semiconductor Thin Films, Calibration and Measurement Techniques. 22 papers and 635 citations.
Add your photo, update your bio, and get notified when your ranking changes.
Single crystals of lead telluride measuring up to 1¼-cm diameter and 6 cm long have been grown in sealed silica crucibles by the Bridgman-Stockbarger method of lowering a melt slowly through a freezing level. The crystals have been grown for the purpose of testing the semiconducting and allied properties of lead telluride in that form. Extreme purity of the materials and cleanliness of the crucible have been found essential for successful growth. X-ray tests have shown that the specimens are single crystals. The purest crystal grown so far had a conductivity corresponding to an electron concentration of 5×1014 per cc. Attempts to introduce excess of one of the constituents—lead or tellurium into the crystal lattice during growth have not so far been successful.
Measurements have been made of the refractive index and absorption index of InSb by reflection methods with polarized radiation. Extensive studies of absorption constant have been made by direct transmission measurements.
Anomalies in the type of conductivity of artificially prepared crystals of lead selenide and lead telluride have been found to be the result of the presence of oxygen. A method has been developed for eliminating oxygen from the specimens by melting the elements into the crucible in an atmosphere of hydrogen. It has also been found possible to grow single crystals of lead sulfide when oxygen is eliminated from the specimen in this way.
Near intrinsic single crystals of grown from the vapor have been used to construct photoconductive detectors for operation at room temperature. Fabrication of the detectors depends on the use of a newly developed chemical etch to reduce the specimens to thicknesses of a few microns, and to provide surfaces with low carrier recombination velocity. The highest detectivity, , achieved was ; Various methods of estimating bulk carrier lifetimes have been used; the value for the best crystal measured was in excess of 4 μsec. The surface recombination velocity of the best etched surface was below 80 cm sec−1. Similar etches can be used for and .