Operation of photovoltaic device () Operation of photovoltaic device(l) Transportation Carrier recombination Quasi-neutral region Diffusion length, L, Carriers move by difFusion L, "D, p Carrier recombination carrier lifetime of hole Use, cm Quasi-neutral [Depletion: Quasi-neutral Quasi-neutral Depletion; Quasi-neutral D,-12(m/sec eglon Carriers move by drifting A.K. Chu, Natonal Sun Yasen Unversity A K Cha, Nated Sun Ya-sen Univers Fundamentals Metal-semiconductor contact e Photovoltaic effect results from_f Band diagram of metal-semiconductor interface incident light on some materials n-setnicondurter , PV effect promotes electrons higher energy conduction ban leaving holes behind . Separation of carriers, electrons ve)and holes(+ve)important to solar cells , +ve and-ve carriers transported fn"h x through material in all directions will now from K Ch, Natoma Sun Yasn Unrversty29 Operation of photovoltaic device(II) A. K. Chu, National Sun Yat-sen University 30 Operation of photovoltaic device(III) A. K. Chu, National Sun Yat-sen University 31 Fundamentals ™ Photovoltaic effect results from incident light on some materials ™ PV effect promotes electrons into higher energy conduction bands, leaving holes behind ™ Separation of carriers, electrons (- ve) and holes (+ve) important to solar cells ™ +ve and –ve carriers transported through material in all directions Surface recombination Surface recombination Bulk recombination 32 Metal-semiconductor contact A. K. Chu, National Sun Yat-sen University