during the third quarter, the practical aspects of making epitaxial solar cells were emphasized by exploring the growth and fabrication of large-area cells. in this work, a significant achievement was the attainment of efficiencies close to 10 with epitaxial cells of 10.8 cm exp 2 area grown on the lowest grade silicon substrate under study. for larger areas (23.1 cm exp 2 ) an efficiency of 7.0 was obtained in the first experiment. the use of low-cost surface preparation techniques was successfully demonstrated for both epitaxial growth and the resultant solar-cell properties. some requirements on the subsequent application of ar coatings are pointed out. work on the use of silane as an alternate gaseous silicon source was extended by exploring growth on umg silicon substrates. the results continue to show equivalent performance for cell structures grown in silane at 1000 exp 0 c with those grown using dichlorosilane at 1100 to 1150 exp 0 c. (era citation 05:033406)