Apollo(R) Thin Film Process Development: Final Technical Report, April 1998 - April 2002

BP Solar first started investigative work on CdTe photovoltaics in 1986. The module product name chosen for the CdTe devices is Apollo?. The deposition method chosen was electrochemical deposition due to its simplicity and good control of stoichiometric composition. The window layer used is CdS, produced from a chemical-bath deposition. Initial work focused on increasing photovoltaic cell sizefrom a few mm2 to 900 cm2. At BP Solar's Fairfield plant, work is focused on increasing semiconductor deposition to 1 m2. The primary objective of this subcontract is to establish the conditions required for the efficient plating of CdS/CdTe on large-area, transparent conducting tin-oxide-coated glass superstrate. The initial phase concentrates on superstrate sizes up to 0.55 m2. Later phaseswill include work on 0.94 m2 superstrates. The tasks in this subcontract have been split into four main categories: 1) CdS and CdTe film studies; 2) Enhanced laser processing; 3) Outdoor testing program for the Apollo? module; and 4) Production waste abatement and closed loop study.