Surface passivation in c-Si solar cells via a double-barrier quantum-well structure for ameliorated performance

Abstract

Modern solar cell technology suffers low surface passivation, high recombination losses at the interface, and dopant diffusion losses that limit solar cell’s efficiency. Therefore, a double-barrier quantum-well (DBQW) structure-based surface passivation contact is introduced here to resolve these shortcomings. In this regard, DBQWs of different thicknesses with stacks of SiOx/ nc-SiOx (3, 5, 8, and 10 nm)/SiOx layers were explored as surface passivation layers and dopant diffusion barriers. Multiple characterizations were utilized to examine DBQW thickness-dependent properties, such as contact resistance, passivation, and recombination current density; the best result was for the 5-nm-thickness QW passivation layer. To justify the obtained result, theoretical calculations were carried out based on the experimental results, which suggested the resonance tunneling of charge carriers across the 5 nm DBQW structure. Furthermore, SIMS was explored to examine the diffusion barrier property of these QWs, which revealed that dopant diffusion was suppressed by the QW with the double SiOx layer. Finally, the nc-SiOx(n) /5-nm QW/c-Si surface passivation structure showed substantial enhancement in a lifetime (τeff) of 3560 μs, an implied open-circuit voltage (iVoc) of 735 mV, and reduced recombination current density (Jo) = 1.5 fA/cm2.