Laser scattering tomographic analysis of cadmium oxalate single crystal

Single Crystals of Cadmium Oxalate trihydrated have been grown using the famous gel technique. Optical investigation methods are easy to perform and non-destructive testing.

The “laser scattering tomography” LST provides a method to investigate the effect which the defects have on the characteristics of solid state devices. The LST is highly effective and dependable for the analysis of microdefects. The technique permits the location being observed to be freely chosen by scanning the laser beam inside the crystal, and has very high sensitivity in the case of extremely small defects, thus making possible the nondestructive observation of the 3 – dimensional distribution of even extremely minute defects. The sensitivity of defect detection by laser tomography is much greater than that with other observation methods. This is because X-rays and light scattering have as a parameter. The detection sensitivity of laser light scattering at micro – defects is of the order of (n m³). The countable numbers of dislocation of the order of 10² to 10³ cm-² which decreases drastically with depth, implies perfection of the grown crystals. This also corroborates to the observation that the as-grown surfaces of crystals, when viewed under an optical microscope, usually contain dense pitting while the cleaved surfaces show less pitting.