the liquid phase epitaxial (lpe) growth of thin gaas films on oxide substrates (mgal sub 2 o sub 4 , al sub 2 o sub 3 , beo single crystals and fused quartz) is investigated for low cost solar cells techniques are developed to prepare substrate surfaces and to control nucleation and growth of gaas from as-saturated ga melts. the furnace and growth cell are designed to study the effects of heating and cooling rates, magnitude and direction of temperature gradients, as saturation, and melt and substrate pretreatments. surface studies by high resolution microscopy appear to indicate that these substrate and gaas surfaces are facetted with a very regular approximately 30 a periodicity which is superimposed on a more irregular 100 to 200 a surface structure. the larger structures were dependent on orientation and influenced by chemical and mechanical polishing. the (111) mgal sub 2 o sub 4 surfaces appear to be smoother than the (100). scratches, defects and edges appear to influence nucleation but not the orientation of the growth. the nucleation on oxide substrates appears to be primarily determined by the as-saturation in the ga melt with no nucleation below approximately 850 exp 0 c. the resultant nucleation density appears to be independent of the cooling rate, supercooling and temperature gradient. nucleation densities on sandblasted fused quartz are very high, but the resultant growth does not adhere. however, growth does tenaciously adhere to polished fused quartz when nucleated on sandblasted areas, but the difference in coefficient of expansion tends to spall the fused