G. Kühn

Ford Foundation

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Research Field

Characterization of the Microhardness of Ion‐implanted GaP

Crystal Research and Technology (1991)

C. Ascheron H. Neumann G. Kühn

Abstract Implantation induced changes of the microhardness are studied in GaP single crystals which were bombarded with ions in the range of mass numbers M = 1–40. It is observed that point defects and incorporated hydrogen have a stronger hardening effect. The effect of defect complexes is lower, and amorphized layers are softer than crystalline layers.

Hardening (computing)

Characterization

10.1002/crat.2170260305

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Citations (12)

Estimation of experimental parameters for the LEC growth of in‐doped GaAs

Crystal Research and Technology (1988)

S. Kulosa G. Kühn

10.1002/crat.2170231227

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Citations (0)

Crystal structures of two quenched CuInSe phases

Crystal Research and Technology (1988)

Wolfgang Hönle G. Kühn U.‐C. Boehnke

Abstract The crystal structures of the δ‐phase with a composition of Cu 0.46 In 1.18 Se 2.00 and of a Cu‐poor β‐phase with a composition of Cu 0.39 In 1.20 Se 2.00 , both quenched from 750 °C, have been determined with single crystals. The δ‐phase crystallizes with a = 576.2(4) pm in the ZnS‐type structure (space group F 4 3m), the β‐phase with a = 575.5(3) pm, c = 1152.0(4) pm and Z = 4 in a new structure type for tetrahedral structures with the space group P 4 2c. In both compounds the cations are statistically distributed together with vacancies. The number of vacancies is estimated from the crystal structure analyses and results to be (Cu 0.54(2) In 1.15(2)□0.30(2) ) Se 2 for the δ‐phase and (Cu 0.36 In 1.09□0.55 ) (Se 1.80□0.20 ) for the Cu‐poor β‐phase.

Crystal (programming language)

Tetrahedron

Structure type

10.1002/crat.2170231027

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Citations (90)

Heat capacity of CuAlTe₂ at elevated temperatures

Crystal Research and Technology (1987)

W. Möller G. Kühn H. Neumann

10.1002/crat.2170220427

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Citations (3)

Infrared Lattice Vibrations in NaGaO₂

Crystal Research and Technology (1991)

H. Sobotta H. Neumann B. Schümann G. Kühn V. Riede

Abstract Infrared reflectivity spectra of NaGaO 2 samples prepared from powdered material are measured at room temperature in the wavenumber range from 180 to 4000 cm −1 . An analysis of the spectra with the Kramers‐Kronig method reveals 16 vibrational modes. From a comparison of the results for NaGaO 2 with previous measurements on the isostructural compound LiGaO 2 conclusions are made with regard to the Ga–O and Na–O bond related vibrational modes.

Isostructural

Lattice vibration

Wavenumber

Lattice (music)

10.1002/crat.2170260612

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Citations (2)

On the Chemical Mechanism of the Zinc Diffusion into GaAs from SiO₂ Spin‐on Films

Crystal Research and Technology (1992)

E. Nowak G. Kühn B. Schümann R. Hesse H. Sobotta

Abstract The chemical processes which take place during annealing were studied in both model substances and thin films deposited onto GaAs wafers by thermal analysis, X‐ray powder diffraction, IR spectroscopy, XPS and TEM. It was found that at 600°C only about 45% of the film was changed to SiO 2 glass. At 700 °C begins the formation of zinc silicates. In this form the zinc seems to be scarcely able to diffuse into GaAs. Obviously, the exothermic DTA effect at 800 °C arises from this zinc silicate formation connected with a recrystallization of the amorphous film.

Recrystallization (geology)

10.1002/crat.2170270415

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Citations (1)

Heat capacity and lattice anharmonicity in CdB^IVC chalcopyrite compounds

Crystal Research and Technology (1987)

W. Möller G. Kühn H. Neumann

Abstract The heat capacity at constant pressure of CdSiP 2 , CdGeP 2 , CdSnP 2 and CdGeAs 2 is measured in the temperature range from 300 to 500 K. The anharmonic contribution to the heat capacity is evaluated and it is shown that the degree of lattice anharmonicity decreases with increasing atomic weight of the constituent atoms of the compounds. Comparing the temperature variation of the heat capacity and of the thermal expansion coefficient some conclusions are made regarding the interatomic potential in the A II B IV C compounds.

Atmospheric temperature range

Lattice (music)

Specific heat

Lattice constant

10.1002/crat.2170220416

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Citations (9)

Heat capacity and thermodynamic properties of LiGaO₂ from 180 to 700 K

Crystal Research and Technology (1987)

H. Neumann G. Kühn Hugo Neels E. Nowak E. Pirl

Abstract The heat capacity at constant pressure of LiGaO 2 is measured in the temperature range from 180 to 700 K. An analysis of the experimental data shows that the anharmonic contribution to the heat capacity can be described by a polynomial of fourth order in the temperature. The standard enthalpies and entropies relative to 298.15 K are calculated from the measured heat capacity. Estimates of the standard enthalpy and entropy at 298.15 K are given.

Heat capacity ratio

Atmospheric temperature range

Specific heat

Sigma heat

10.1002/crat.2170220322

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Citations (5)

A Novel Electrostatic Machine: the Corona Motor

Nature (1961)

J. D. N. van Wyk G. Kühn

Electrostatics

Corona (planetary geology)