Development of thin film GaAs p-i-n solar cells peeled-off from Si substrates

III-V group semiconductor solar cells are the most efficient photovoltaic technologies. In particular, III-V group based GaAs solar cells provide excellent optical properties, good electronic speed, and higher radiation resistance over conventional Si solar cells. However, the high prices of single crystal III-V based wafers restrict the use of GaAs in photovoltaic applications. As a result, cost-cutting approaches for III-V solar cells have piqued the interest of many researchers. The epitaxial lift-off (ELO) method has been receiving much interest for producing flexible, lightweight, and high-efficient solar cells. The method also allows for the reuse of pricey III-V substrates for subsequent growths, reducing overall cost. Heteroepitaxial growth of III-V semiconductors on low-cost Si substrates, on the other hand, is another method for reducing the cost of GaAs solar cells. Using Si substrates also allows for large-scale production of III-V solar cells. In this thesis, GaAs solar cells were grown on Si substrates using a molecular beam epitaxy (MBE) system. GaAs solar cells were designed as p-i-n type junctions to improve charge extraction. The effects of various types of dislocation filter approaches were compared to achieve the best crystal quality. Before and after the ELO process, optical and structural characterizations of solar cell structures were performed. The energy conversion and quantum efficiency values of the solar cell were measured. Thin-film GaAs p-i-n solar cells peeled off from Si substrates have achieved 8.81% energy conversion efficiency under the 1.5AMG spectrum.