Abract This paper concems studies of CIS solar cell based on ZnSe an ZnSeTe window layer. ZnSe an ZnSeTe films are grown by Molecular Beam Deposition (MBD).This research is important for several reasons : (1)Development of non-cadmium buffer layer may be essential for CIS solar cells to be accepted in the marketplace ; (2)Development of direct ZnO/CIS cells could lead to a simplified cell (3)knowledge gained in investigations of ZnO and ZnSeTe buffer layer may help us understand the unique role CdS plays in CdS/CIS solar cell .