Dual functions of anti-reflectance and surface passivation of the atomic layer deposited Al2O3 films on crystalline silicon substrates

TL;DR

This study demonstrates that atomic layer deposited Al2O3 films on crystalline silicon serve dual functions by significantly reducing reflectance to about 2.8% and enhancing surface passivation, thereby improving solar cell efficiency.

Contribution

It reveals the dual anti-reflectance and passivation capabilities of Al2O3 films on silicon, with detailed performance improvements after deposition and annealing.

Findings

Reflectance reduced to ~2.8% with 100 nm Al2O3

Minority carrier lifetime increased from ~10 μs to over 3 ms

Effective dual-function for solar cell applications

Abstract

Surface anti-reflectance and passivation properties of the Al2O3 films deposited on crystalline Si substrates by atomic layer deposition are investigated. Textured Si with 100 nm Al2O3 shows a very low average reflectance of ~2.8 %. Both p-type and n-type Si wafers are well passivated by Al2O3 films. The maximal minority carrier lifetimes are improved from ~10 {\mu}s before Al2O3 passivation to above 3 ms for both p-type and n-type Si after Al2O3 passivation layer deposition and annealing at an appropriate temperature. Our results indicate the dual functions of anti-reflectance and surface passivation in c-Si solar cell applications.