TECHNOLOGY FOCUS - ELECTRONICS - Preferred Method: The method (I) further comprises: prior to forming the first electrode layer transferring the substrate to a fifth process station and forming a barrier layer overlying the surface region of the substrate at the fifth process station using a fifth process; prior to forming the p-type absorber layer transferring the substrate to a sixth process station and forming a barrier layer overlying the first electrode layer at the sixth process station using a sixth process; and prior to forming the second electrode layer transferring the substrate to a seventh process station and forming a resistive layer overlying the n-type window layer at the seventh process station using a seventh process. In method (I): transferring the substrate comprises transferring the substrate under reduced pressure; transferring the substrate comprises transferring the substrate in an ambient comprising nitrogen or argon. The method (II) further comprises: prior to forming the first electrode layer transferring the substrate to a fifth process station and forming a barrier layer overlying the surface region of the substrate at the fifth process station; and prior to forming the window layer transferring the substrate to a sixth process station and forming a resistive layer overlying the electrode layer at the sixth process station. The method (III) further comprises: prior to forming the n-type tunnel junction layer, forming a first resistive layer overlying the first window layer, where the first resistive layer is characterized by a resistivity of greater than 10 kohm-cm; and prior to forming the second electrode layer, forming a second resistive layer overlying the second window layer. The method (I), (II) and (III) further comprises in-situ monitoring properties of each layer being formed at each process station and determining a process condition for a subsequent process based on data obtained in the monitoring of at least one earlier processes. The method (IV) further comprises: prior to forming the second electrode layer, forming a first resistive layer overlying the first n-type window layer; and prior to forming the third electrode layer, forming a second resistive layer overlying the second n-type window layer. Preferred Components: The substrate: comprises silicon, germanium, a compound semiconductor material, germanium or silicon-germanium; and is transparent and comprises glass, quartz or fused silica. The first conductor layer comprises: aluminum or tungsten; a transparent conducting oxide material including zinc oxide: aluminum, tin oxide: fluorine or indium tin oxide; and a conductive polymer material. The second conductor layer comprises a transparent conducting oxide material including zinc oxide: aluminum, tin oxide: fluorine or indium tin oxide. EXAMPLE - No suitable example given.