Control of CVD-deposited ZnO films properties through water/DEZ ratio: Decoupling of electrode morphology and electrical characteristics

In thiswork,itisshownthatvariationsintheratioofoxygentozincprecursorsatconstant temperatureallowchangingthesurfacemorphologyofzincoxide(ZnO)filmsdepositedbylow- pressuremetalorganicchemicalvapordeposition,whilekeepingthesheetresistanceandtransparency of thelayersconstant.ThisallowsdevelopingZnOlayerscombininginterestingpropertiessuchaslow surface roughness(below15nm)andlowsheetresistance(below15 O/&). Moregenerally,itisshown that thepyramidalfeaturedensitycanbecontrolledbytuningtheprecursorflows.Thisleadstofilm surfacescharacterizedbyzoneswitharoughmorphologymixedwithzoneswithalmostflatfeatures. Therefore,byusingthistechnique,thelight-scatteringabilityofafilmcanbecarefullytunedthrough its surfacemorphologywithoutaffectingtheconductivityortransparencyofthelayer.Thisprovidesan efficienttooltooptimizethefrontelectrodeofthin-filmsiliconsolarcellstoachievethebestpossible combinationofopen-circuitvoltage,fillfactorandphoto-generatedcurrent.Thepresentedsolutionis an in-situprocessachievableinstandarddepositionconditionsmakingiteasilyup-scalablewith existingproductionequipment.