Optimized resonant tunnelling structures with high conductivity and selectivity

ARC Photovoltaics Centre of Excellence, UNSW - Sydney-2052, Australia

^a binesh@student.unsw.edu.au

Received: 8 August 2011
Accepted: 13 October 2011

Abstract

An improved design for double-barrier resonant tunnelling structures using silicon quantum dots (QDs) was quantitatively analyzed using a multi-mode scatter matrix method. Multilayer metal-barrier-QD/matrix-barrier-metal stacks that maximize both electron transport and confined energy are sought. Si QDs grown in silicon dioxide with silicon carbide barriers were the most advantageous combination for single QD layer double-barrier structures (DBSs). Lateral SiO₂ barriers provided greater confinement, especially in smaller dots and also caused increased splitting between resonant levels. These structures are excellent candidates for use as energy selective contacts (ESCs) and as layers in all-silicon tandem cells.