Thinfilmsiliconsolarcellsforspaceapplications: Study of proton irradiation and thermal annealing effects on the characteristics of solar cells and individual layers J. Kuendig a, *,M.Goetz a ,A.Shah a ,L.Gerlach b ,E.Fernandez b a Institute of Microtechnology (IMT), Thin-film silicon and Photovoltaic group, University of Neuch # atel, A.-L. Breguet 2, 2000 Neuch # atel, Switzerland b ESA-ESTEC, Keplerlaan 1, NL 2200 AG Noordwijk, The Netherlands Abstract The paper reports on the effects of a proton irradiation campaign on a series of thin-film siliconsolarcells(single-anddouble-junction).Theeffectofsubsequentthermalannealingon solar cells degraded by proton irradiation is investigated. A low-temperature annealing behaviourcanbeobserved(attemperaturesaround100to160  C)formicrocrystallinesilicon solar cells. To further explore this effect, a second proton irradiation campaign has been carried out, but this time on microcrystalline silicon layers. The effect of proton irradiation andsubsequentthermalannealingontheopticalandelectronicpropertiesofmicrocrystalline silicon is, thus, thoroughly investigated. Keywords: Thin film solar cell; Microcrystalline; Proton irradiation; Annealing 1. Introduction Solarcellsinspacearehighlyexposedtoprotonradiation.Ithasbeenshownthat CIS [1] and thin-film amorphous silicon [2] solar cells have far higher radiation hardness when compared to conventional Si and GaAs devices. The power/weight ratioofthin-filmsolarcellsisverypromisingforspaceapplications,whereweightis *Corresponding author. E-mail address: jamil.kuendig@unine.ch (J. Kuendig). URL: http://www-micromorph.unine.ch. Published in Solar Energy Materials and Solar Cells 79, issue 4, 425-438, 2003 which should be used for any reference to this work 1