“…These have distinct advantages, viz., large packing density, mass replication, fast data rate, high signal-to-noise ratio and high immunity to defects [1][2][3][4][5]. Among amorphous semiconductors, glassy chalcogenides (Se, Te, S) are more important because they have great varieties of band gaps and are transparent in IR region [6]. Recently, various workers [7][8][9][10] have reported the use of these materials for reversible optical recording by amorphous to crystalline phase change.…”