• Kohl, Thierry

Abstract

<jats:p>In this work, hafnium oxide layer is investigated as rear surface passivation layer for ultra-thin (550 nm) CIGS solar cells. Point contact openings in the passivation layer are realized by spin-coating potassium fluoride prior to absorber layer growth. Contacts are formed during absorber layer growth and visualized with scanning electron microscopy (SEM). To assess the passivating qualities, HfO<jats:sub>x</jats:sub> was applied in a metal-insulator-semiconductor (MIS) structure, and it demonstrates a low interface trap density in combination with a negative density of charges. Since we used ultra-thin devices that are ideal to probe improvements at the rear, solar cell results indicated improvements in all cell parameters by the addition of 2 nm thick HfO<jats:sub>x</jats:sub> passivation layer with contact openings.</jats:p>

Topics

• density
• impedance spectroscopy
• surface
• scanning electron microscopy
• semiconductor
• Potassium
• hafnium
• hafnium oxide