Studies on ion-beam modifications of ADP and KDP crystal surfaces

Abstract

Experimental investigations on He+ ion (150 keV) beam modifications of the (100) surfaces of ADP and KDP single crystals, relative to asgrown surfaces have been made, to assess the nature and extent of radiation damage. Studies on the surface micromorphology, defect substructure, defect concentration, surface conductivity and microhardness have been made. Studies on chemical etching in both ion irradiated and asgrown surfaces revealed drastic changes in etchpit morphology and defect concentration. Measurement of surface electrical conductivity, employing four-point probe method, showed enhancement in conductivity at all the temperatures of observation which is attributed to enhanced proton migration. Measurement of microhardness and studies on planar plastic anisotropy in asgrown surfaces relative to ion bombarded surfaces have been made employing Knoop indenter and the results are interpreted in terms of the nature of bonding, bond strength and radiation damage on ion bombardment. Plastic anisotropy in these surfaces is found to be in conformity with the (100) plane on which the indentations were made.