The Application Of A-Si:H/Alox Stack As An Electron Selective Contact On N-Type Silicon Solar Cells

In this report, we present a novel application of ALD (atomic layer deposition) deposited aluminum oxide (AlOx) combined with a passivation layer of a-Si:H(i) (hydrogenated intrinsic amorphous silicon) as electron selective contacts (ESCs) on n-type silicon (n-Si) solar cells. Band alignment profiles of n-Si/Al, n-Si/AlOx/Al and n-Si/a-Si:H(i)/AlOx/Al structures are presented, suggesting the feasibility of electron-selectivity, and explaining the transformation from a Schottky behaving contact to an ohmic contact. As proof, a rectifying Al contact on n-Si is observed to be ohmic after the inclusion of an AlOx interlayer. A contact resistivity as low as 3.45 +/- 0.005 m Omega center dot cm(2) is obtained. Finally, a cell achieving an open-circuit voltage of around 590 mV has been fabricated to demonstrate the feasibility of this contact technique.