New progress in the fabrication of n–i–p micromorph solar cells for opaque substrates

In thispaper,weinvestigatetandemamorphous/microcrystallinesiliconsolarcellswithasymmetric intermediatereflectorsgrowninthen–i–psubstrateconfiguration.Wecomparedifferenttypesof substrateswithrespecttotheirlight-trappingpropertiesaswellastheirinfluenceonthegrowthof single-junctionmicrocrystallinecells.Ourmostpromisingbackreflectorcombinesatexturedzinc oxide filmgrownbylow-pressurechemicalvapordeposition,asilverfilmforreflection,andazinc oxide bufferlayer.Grownonthissubstrate,microcrystallinecellsexhibitexcellentresponseinthe infrared whilekeepinghighopen-circuitvoltageandfillfactor,leadingtoefficienciesofupto10.0%. After optimizingthemorphologyoftheasymmetricintermediatereflector,weachieveann–i–p micromorphsolarcellstabilizedefficiencyof11.6%,using270nmand1.7 mm ofsiliconfortheabsorber layer oftheamorphoustopcellandthemicrocrystallinebottomcell,respectively.Usingthisoriginal devicearchitecture,wereachefficienciesclosetothoseofstate-of-the-artn–i–pandp–i–nmicro- morph devices,demonstratingapromisingroutetodeposithigh-efficiencythin-filmsiliconsolarcells on opaquesubstrates.