Zhong Lu (36Min)

UNSW SPREE

Abstract

This talk explores the incorporation of Anodic Aluminium Oxide (AAO) into silicon solar cell structures to achieve localized contact and enhanced passivation. It is shown that localized contacts can be achieved with low contact resistance of ~ 6 mΩ.cm² at 5% contact percentage. A method of fabricating AAO with a controllable stored charge is developed to optimize the passivation of various types of Si surfaces. This method involves the use of a pulse current source to anodize aluminium layers instead of the typically-used constant current/voltage source, with the test structures experiencing positive and negative cycles periodically. By tuning the positive cycle percentage, it is demonstrated that the effective stored charge density can be reliably manipulated in a range from –5.2 × 10¹¹ to 2.5 × 10¹² q/cm² when the AAO is formed over a thin SiO₂ layer. The investigation of the stored charge distribution in the dielectric stacks indicates a positive fixed charge at the SiO₂/Si interface, a negative fixed charge at the AAO/SiO₂ interface and a positive bulk charge in the AAO layer.

Brief Bio

Zhong Lu received his Bachelor of Engineering degree from UNSW in 2011 with a first class honor and a University Medal. He started his PhD in photovoltaic engineering at UNSW in 2012 with an IPRS (and later an APA) scholarship. He developed a method of fabricating AAO with a controllable stored charge for semiconductor passivation. His research focuses on the applications of this method to passivate silicon surfaces and on C-V characterization of MIS structures.