Raman microspectroscopy provides the means to obtain local orientations on polycrystalline materials at the submicrometer level. The present work demonstrates how orientation-distribution maps composed of Raman intensity distributions can be acquired on large areas of several hundreds of square micrometers. A polycrystalline CuInSe2 thin film was used as a model system. The orientation distribu...

A novel method for obtaining position resolved information simultaneously from an entire plane of a polycrystalline or amorphous sample using the diffracted radiation or fluorescence has been developed. It makes use of a microchannelplate as a collimator in front of a position sensitive detector (CCDcamera). Experiments may be performed either in transmission or in reflection geometry. In the f...

Important physical properties such as yield strength, elastic modulus, and thermal conductivity depend on the material microstructure. Realization of optimal microstructures is important for hardware components in aerospace applications where there is a need to optimize material properties for improved performance. Microstructures can be tailored through controlled deformation or heat treatment...

A phenomenological constitutive law is developed for the deformation of polycrystalline ferroelastic materials. The model is framed within a thermodynamic setting common to internal variable plasticity. The two significant inputs to this model are a switching (yield) surface, and a hardening potential. To maintain simplicity, the shape of the switching surface is assumed to be spherical in a mo...

We investigated the thermoelectric properties of Cl-doped polycrystalline compounds In4Pb0.01Sn0.03Se2.9Clx (x = 0.02, 0.04, and 0.06). X-ray diffraction measurement shows a gradual change in lattice volume for x ≤ 0.04 without any impurity phases indicating a systemic change in Cl doping. The Cl doping in the compounds has the effect of increasing carrier concentration and the effective mass o...

An ultrasonic wave propagating through a microscopically inhomogeneous medium, such as polycrystalline materials, is subject to scattering at the grain boundaries as well as other inhomogenities. The fraction of energy removed from the incident wave is responsible for important phenomenon like attenuation, dispersion, and background “noise" associated with a given ultrasonic inspection system. ...

An analytical formula is developed for the evolution of angular dependence of sputtering yields by extending the theory of sputtering yield proposed by Sigmund. We demonstrate that the peak of sputtering yield at oblique incidence can be attributed to a balance between the increased energy deposited on the surface by incident ion which enhances the sputtering yield and the decreased depth trave...

We use the combination of high-resolution electron microscopy and density-functional theory to study the atomic structure and electronic effects of grain boundaries in polycrystalline photovoltaic materials such as Si, CdTe, CuInSe2, and CuGaSe2. We find that grain boundaries containing dislocation cores create deep levels in Si, CdTe, and CuGaSe2. Surprisingly, however, they do not create deep...

Atomic defects in crystalline structures have pronounced affects on their bulk properties. Aberration-corrected transmission electron microscopy has proved to be a powerful characterization tool for understanding the bonding structure of defects in materials. In this article, recent results on the characterization of defect structures in two dimensional materials are discussed. The dynamic beha...