Thin-Film CIGS Photovoltaic Technology; Annual Technical Report, Phase I; 16 April 1998 - 15 April 1999

This report describes work performed by Energy Photovoltaics, Inc. (EPV) under Phase I of this subcontract. EPV's new FORNAX process for CIGS formation is capable of producing devices with high V{sub oc} (>600 mV) and no dark aging effects. Parameters of the best device so far are V{sub oc} = 611 mV, J{sub sc} = 27.5 mA/cm{sup 2}, FF = 74.5%, and efficiency = 12.5%. A 34-cm{sup 2} 16-cell minimodule was produced using FORNAX CIGS with V{sub oc} = 9.58 V, I{sub sc} = 52.0 mA, FF = 69.8%, and efficiency = 10.2%. A new version of EPV's linear evaporation source was developed with improved rate and uniformity for Cu deposition over a width of 45 cm. Using the new linear source, the FORNAX process was implemented on 0.43-m{sub 2} substrates in EPV's CIGS pilot line, with V{sub oc} = 537 mV and FF = 70.3% being achieved on a device. The EPV Subteam of the National CIS R&D Team has produced Cd-free ZnO/CIGS devices on NREL CIGS using the ROMEAO process (reaction of metal and atomic oxygen) for ZnO deposition. After soaking, the best device exhibited a V{sub oc} of 565 mV and an efficiency of 12.3%. Novel bias drive methods were devised for field soaking/anti-soaking experiments as a function of time and temperature. Scaling laws and an activation energy of 0.51 eV were found. Thermally stimulated capacitance reveals the existence of three distinct contributions to ZnO/CIGS device capacitance, two appearing to be gap-state effects and one related to net doping concentration. The coating time of the sputtered pilot-line ZnO:Al has been reduced by a factor of 3 while maintaining film quality. The deposition rate is 48 A s{sup -1}. Plans are under way to increase the substrate size from 0.43 m{sup 2} to 0.79 m{sup 2}

1. A vasodilator nervous pathway to the cerebral vessels from the central nervous system. 2. On the occurrence of afferent nerve fibers in the internal carotid plexus.

Already Nothnagel's (1867) experiments made on vasomotor innervation of the pial arteries, lead him to suggest the presence of some ·other vaso-motor pathways from the central nervous system to the pial arteries than that represented by the cervical sympathetic trunk. He pointed to the cranial nerves, commnnicating with the internal carotid nerve, as the other possible routes for these vaso-motor nerve fibers. [...