Structures and Optical Behavior of Overcoated Granular Films

In t h e l a s t t e n y e a r s , t h e r e h a s been a c o n s i d e r a b l e i n c r e a s e i n i n t e r e s t r e g a r d i n g t h e e l e c t r i c a l a n d o p t i c a l p r o p e r t i e s o f d i s c o n t i n u o u s m a t e r i a l s due t o t h e i r many p o s s i b l e a p p l i c a t i o n s 1 . In p a r t i c u l a r t h i n g r a n u l a r m e t a l f i l m s e x h i b i t s e l e c t i v e a b s o r p t i o n i n t h e v i s i b l e s p e c t r u m . The f i l m p r o p e r t i e s depend l a r g e l y on t h e s i z e , s h a p e and d i s t r i b u t i o n o f t h e p a r t i c l e s on t h e s u b s t r a t e 2 . In t h e p r e s e n t work , Ag and C u g r a n u l a r f i l m s o v e r c o a t e d w i t h a t h i c k meta l l a y e r have been i n v e s t i g a t e d . By e x a m i n i n g t h e o p t i c a l b e h a v i o r o f t h e s e f i l m s i n t h e s p e c t r a l r a n g e from 0 . 3 t o 1 . O m i c r o n , o n e i s a b l e t o d r a w q u a l i t a t i v e c o n c l u s i o n s a b o u t t h e s t r u c t u r e o f t h e o v e r c o a t e d f i l m s .