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

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 SiO_x/ nc-SiO_x (3, 5, 8, and 10 nm)/SiO_x 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 SiO_x layer. Finally, the nc-SiO_x(n) /5-nm QW/c-Si surface passivation structure showed substantial enhancement in a lifetime (τ_eff) of 3560 μs, an implied open-circuit voltage (iV_oc) of 735 mV, and reduced recombination current density (J_o) = 1.5 fA/cm².