Issue 40, 2017

Addressing carrier extraction from optically-optimized nanopillar arrays for thin-film photovoltaics

Abstract

Decorating the top surface of silicon solar cells with nanopillar arrays of subwavelength periodicity is a promising path toward low-cost thin-film photovoltaics with enhanced solar radiation absorption due to the inherent light trapping capabilities of nanopillar arrays. Common practice and knowledge for the efficient carrier extraction from the excited nanopillars is the formation of ultra-shallow radial p–n junctions that provide both short carrier collection lengths, and also ensure that the volume of the photo inactive emitter is as small as possible. In the current manuscript, both finite-difference time-domain simulations and three-dimensional device simulations are used to examine carrier extraction from nanopillar arrays that are geometrically optimized in terms of array periodicity and nanopillar diameter to provide maximum absorption of the solar spectrum. The discussion is limited to nanopillars with heights of 2 μm in line with what is currently available with leading top-down fabrication technologies for the formation of nanopillars with smooth sidewalls and radial uniformity. The examination considers both radial and axial homojunctions for various junction depths. It is shown that, contrary to common practice and knowledge, the ultra-shallow junctions are detrimental to the photovoltaic performance of such systems while the radial configuration with a junction depth of ∼50 nm is the most efficient. Furthermore, the open circuit voltage is highest for axial junctions with a junction depth of 100 nm. Also, it is shown that the axial junction is preferable in the low dopant concentration regime and that overall, the axial junction is less sensitive to variations in junction depth.

Graphical abstract: Addressing carrier extraction from optically-optimized nanopillar arrays for thin-film photovoltaics

Article information

Article type
Paper
Submitted
16 Jul 2017
Accepted
04 Oct 2017
First published
05 Oct 2017

Nanoscale, 2017,9, 15707-15716

Addressing carrier extraction from optically-optimized nanopillar arrays for thin-film photovoltaics

G. Shalev, Nanoscale, 2017, 9, 15707 DOI: 10.1039/C7NR05172G

To request permission to reproduce material from this article, please go to the Copyright Clearance Center request page.

If you are an author contributing to an RSC publication, you do not need to request permission provided correct acknowledgement is given.

If you are the author of this article, you do not need to request permission to reproduce figures and diagrams provided correct acknowledgement is given. If you want to reproduce the whole article in a third-party publication (excluding your thesis/dissertation for which permission is not required) please go to the Copyright Clearance Center request page.

Read more about how to correctly acknowledge RSC content.

Social activity

Spotlight

Advertisements