Transparent Hole-Selective Contacts for Crystalline Silicon Solar Cells using Molybdenum Oxide and a Thin Aluminum Oxide Passivation Layer

The amorphous silicon layers in silicon heterojunction solar cells absorb light in the short wavelength region of the solar spectrum, lowering the generation current available to the device. Here, we present an alternative to the hole-selective amorphous silicon layers using only wide-bandgap oxide materials. Using thermal ALD, we deposit a 1 nm hydrogenated aluminum oxide layer followed by a 4 nm molybdenum oxide layer on n-type crystalline silicon. We show that this contact provides good surface passivation while remaining thermally stable up to 200°C.