Variable temperature surface photovoltage imaging of oxide and nitride coated multicrystalline silicon solar cells

State-of-the-art, high volume, solar cell production techniques involve multicrystalline silicon (mc-Si) substrates with screen printed electrical contacts. Silicon nitride (Si₃N₄) coated cells have been shown to have higher efficiencies than cells using silicon oxide; however, a relatively unexplored area is the effect of higher substrate temperatures. Surface photovoltage analysis of Si₃N₄ indicates an unexpected enhancement of surface trapping with increased substrate temperature. The chapter shows that surface potential (~sp) images at the mc-Si grain boundaries due to different Si polytypes. The scanning Kelvin probe (SKP) determines changes in ~sp as a vibrating metal tip is moved across the solar cell in a non-contact fashion. The SKP platform used for the studies was the KP Technology Ltd model SKP4G, readers are directed for further high-resolution colour scans. The chapter investigates surface features such as grain boundaries, trapped charge, and emitter electrical characteristics using surface potential imaging.