Galvanomagnetic measurements as a function of temperature between 77 °K and 273 °K in single crystals of antimony are presented. Results are interpreted in terms of the two-carrier multi-valley band model to obtain carrier mobilities, densities and details of the nature of the Fermi surface. The temperature dependences of the mobilities of holes and electrons are found to be T-1 48 and T-1 42 respectively. Contrary to the usual assumption, the electrons are sited in pockets with a small angle of tilt (5°) away from the trigonal axis, while the extrema containing holes have a large tilt angle (24°). Carrier densities are almost independent of temperature, ranging from 3 9 × 1019 cm-3 at 77 °K to 4 2 × 1019 cm-3 at 273 °K for both electrons and holes. If, as recent work indicates, there are three pockets of electrons and six of holes, then at 273 °K each electron ellipsoid contains 1 4 × 1019 electrons/cm3 and each hole pocket 0 7 × 1019 holes/cm3.

Galvanomagnetic properties of single-crystal antimony between 77 °K and 273 °K

In this paper experiments on photoluminescence (emission and excitation spectra) of CdIn2S4 crystals and of mixed crystals with In2S3 at 77°K are reported. The results are interpreted on the basis of the partial inversion of the thiospinel CdIn2S4. In CdIn2S4 the two emission bands observed in the red spectral region are ascribed to a Cd ion at an octahedral site and an In ion at a tetrahedral site. This model describes the intensity and wavelength variation of the photoluminescence of the mixed crystal system CdIn2S4/In2S3 surprisingly well. Evidence is given that the energy gap in all these crystals is indirect. In an appendix some etching procedures are listed.



In dieser Arbeit wird uber Photolumineszenz-Experimente (Emissions- und Anregungsspektren) an CdIn2S4-Kristallen und an Mischkristallen mit In2S3 berichtet. Die Messungen wurden bei 77°K ausgefuhrt. Die Resultate werden auf Grund der teilweisen Inversion des Spinelgitters von CdIn2S4 erklart. Im roten Spektralbereich werden zwei Emissionsbanden beobachtet, die je einem Cd-Ion auf Oktaederplatz und einem In-Ion auf Tetraederplatz zugeordnet werden konnen. Mit diesem Modell last sich sowohl die Intensitat als auch die Wellenlangenabhangigkeit der Photolumineszenz im Mischkristallsystem CdIn2S4/In2S3 uberraschend gut beschreiben. Ferner werden Hinweise diskutiert, die vermuten lassen, das der Band–Band-Ubergang in allen untersuchten Kristallen indirekt ist. Im Anhang sind einige Atzvorschriften zusammengestellt.

Photoluminescence of CdIn2S4 and Mixed Crystals with In2S3 as Related to Their Structural Properties

Dislocation studies in Bi2Te3 were made by etch‐pit technique. All work was done on c planes. The etch marks the dislocations in the c plane by producing etch grooves, and marks the sites of emergence of dislocations from the surface with pyramidal etch pits. Evidence was found for the presence of networks of dislocations lying predominantly in the c plane. Experimental evidence was also found for bending of the dislocations within the crystal being responsible for different size pyramidal etch pits, and flat bottom pits observed on the etched surfaces. The same mechanism was found to be responsible for bringing out new etch pits on longer etching. The slip traces on the c plane were found by controlled surface‐damage studies to be parallel to the binary axes.

Dislocation Studies in Bi2Te3 by Etch‐Pit Technique

A chemical etch has been developed to reveal dislocations on the (111) plane of high‐purity copper without prior decorating. By the use of this etch, we have observed that dislocation climb and polygonization did not occur after annealing bent single crystals near the melting point, in agreement with the x‐ray results of other investigators.

Dislocation Etch Pits and Polygonization in High‐Purity Copper

The elastic constants and interatomic binding forces in arsenic

Pits which are probably the sites of dislocations have been produced on the (111) cleavage planes of antimony by use of the CP4 etching reagent. Evidence that the pits probably are at dislocation sites was obtained from density counts on intersecting boundaries and from deformation and annealing studies. The Dash etching reagent chemically polishes antimony without producing pits. The Superoxol etch brings out spiral terraced pits and other fine structure.

J. N. Hobstetter

Papers

Dislocation Etch Pits in Antimony