Influence of PECVD SiO_x and SiN_x:H films on optical and passivation properties of antireflective porous silicon coatings for silicon solar cells

Abstract

The meso‐porous silicon layer (PS) is a promising material to reduce the surface reflectance of solar cells. PS layers were grown on the front surface n+ emitter of n+‐p mono‐crystalline Si junction. Single layers PS antireflection coating (ARC) achieved around 8% of effective reflectivity in the wavelength range between 400 to 1100 nm. To improve the stability and the passivation properties, and to reduce the reflectivity of PS ARC, the design of PECVD silicon oxide (SiOx) and silicon nitride (SiNx:H) layers were investigated. Optimised SiOx and SiNx layer deposited on PS decreased the effective reflectivity respectively to ∼3.8% and ∼7% between 400 and 1000 nm. Open circuit voltage (Voc) measurements were carried out on all the samples by suns‐Voc method and showed an improvement of 20% of the surface passivation quality brought by the nitride layer after rapid thermal anneal (RTA). Using the experimental reflectivity results and taking into account the surface passivation quality of the samples, numerical simulations predict an enhancement of the photogenerated current exceeding 49% for the PS/SiOx stacks (© 2011 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Optical properties of porous Si/PECVD SiNX:H reflector on single crystalline Si for solar cells

“…The deposition of a silicon nitride (SiN x :H) layer over the PS layer may be an alternative solution. Indeed, we have demonstrated experimentally in the previous paper [32], that the silicon nitride layer deposited over the PS layer on the front surface of a solar cell improved the passivation properties by more than 20 %.…”

Effect of the Back Surface Reflector and Passivated Rear Contacts With PERT Solar Cells

“…For the passivation of the BSF diffusion, three different dielectric passivation layers were applied: a standard antireflection SiN x , the thermal silicon oxide SiO 2 and a stack of SiN x /SiO 2 [11]. For rear contacts, we used local point contacts by 10 µm by 10 µm small windows with a spacing of 250 µm.…”

“…(11) Where ∆n is excess carrier concentration, Using S rear and J rear we extract the saturation current density J rear-cont from samples that feature laser-contacted boron-diffused layers with opening fraction f by plotting the inverse effective lifetime τ eff versus the excess carrier concentration ∆n using the equation [6] (12)…”

Optimization of Antireflection Coating Design Using PC1D Simulation for c − Si Solar Cell Application

“…Several researchers employed various ARCs that might be used to increase the efficiency of the solar cell. Thin films such as TiO 2 , SiO 2 , SiN x , Al 2 O 3 etc., were used as ARC layers [7][8][9][10][11]. TiO 2 was a commonly used ARC on the front surface, owing to its versatility and inexpensive [7].…”