Self-assembled Al nanoparticles on Si and fused silica, and their application for Si solar cells

• Published in: Nanotechnology 2013-07, Vol.24 (27), p.275606-275606
• Main Authors: Villesen, T F, Uhrenfeldt, C, Johansen, B, Nylandsted Larsen, A
• Format: Article
• Language: English
• Subjects: Aluminum; Applied sciences; Cross-disciplinary physics: materials science; rheology; Energy; Exact sciences and technology; Materials science; Methods of nanofabrication; Nanocrystalline materials; Nanoscale materials and structures: fabrication and characterization; Natural energy; Photovoltaic conversion; Physics; Self-assembly; Solar cells. Photoelectrochemical cells; Solar energy
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/24/27/275606

This paper presents a novel method for the self-assembly of aluminum nanoparticles on Si and fused silica. Due to high reactivity with oxygen, ex-vacuo annealing of thin deposited metal films, a method used extensively with other metals, does not work with aluminum. In the present experiment this problem was overcome by annealing the samples in-vacuo in the deposition chamber. Aluminum was thermally evaporated onto substrates at elevated temperatures (200-400 ° C) and annealed for 60 min without breaking the vacuum. It is shown that at 300 and 400 ° C the average particle size can be controlled by adjusting the amount of evaporated aluminum. Particle diameters ranging from 20 to 130 nm are demonstrated. These particles support localized surface plasmon resonances, a property that can be utilized for enhancing the efficiency of thin Si solar cells. This is explored here, and an increase in external quantum efficiency of up to 15% in a thin-film Si solar cell is demonstrated.