Optimised Antireflection Coatings for Planar Silicon Solar Cells Using Remote PECVD Silicon Nitride and Porous Silicon DioxideH. Nagel, A. G. Aberle, and R. Hezel Literature Review by George Burdell
Discussion Topics • Significance of Paper • Antireflection materials for photovoltaic (PV) devices • Experimental measurements of optical constants • Background and Motivation • Summary of Paper • Conclusions
Significance of Paper • Measurement of optical constants • Antireflection coating materials • Titanium dioxide and porous silicon dioxide • Silicon nitride by remote plasma-enhanced chemical vapor deposition (remote PECVD) • PV module encapsulation materials • B270 and soda lime glasses • EVA and resin pottants • Optimization of novel antireflection coatings
Background and Motivation • Passivating antireflection coatings • Reduced reflectance • Reduced surface recombination • PECVD silicon nitride (SiNX) • Achieves both objectives • Has well-controlled manufacturing process • Is economically viable • Exhibits parasitic absorption
Antireflection Coating Design • Encapsulated solar cell • n1: encapsulation • n2: coating material • ns: silicon • Coating material (blue) • Fresnel equations give optimum index • Extinction coefficient neglected
Passivating Antireflection Coatings Source: A. Rohatgi, et al., “Comprehensive study of rapid, low-cost silicon surface passivation technologies,” IEEE Transactions on Electron Devices, vol. ED-47, no. 5, pp. 987–993, 2000.
Summary of Paper • Experimental measurement of optical constants • Analysis of transmission and reflection • Monochromator and integrating sphere • Numerical optimization of antireflection coatings • Remote PECVD SiNX vs. other materials • Realistic data for encapsulant materials • No investigation of combined effect of antireflection and passivation
Conclusions • New optical data available for PV materials • Remote PECVD SiNX • Encapsulant materials • Numerical antireflection coating optimization required for absorbing materials • Combined impact of surface passivation and antireflection coating still not fully quantified