A tunable amorphous p-type ternary oxide system: the highly mismatched alloy of copper tin oxide
journal contributionposted on 16.10.2015, 12:56 by Patrick IsherwoodPatrick Isherwood, K.T. Butler, A. Walsh, Michael WallsMichael Walls
The approach of combining two mismatched materials to form an amorphous alloy was used to synthesise ternary oxides of CuO and SnO2. These materials were analysed across a range of compositions, and the electronic structure was modelled using density functional theory. In contrast to the gradual reduction in optical band gap, the lms show a sharp reduction in both transparency and electrical resistivity with copper contents of greater than 50 %. Simulations indicate this change is caused by a transition from a dominant Sn 5s to Cu 3d contribution to the upper valence band. A corresponding decrease in energetic disorder results in increased charge percolation pathways: a `compositional mobility edge'. Contributions from Cu(II) sub band-gap states are responsible for the reduction in optical transparency.
The authors are grateful to RCUK for financial support through the SuperSolar Hub (EPSRC Grant No.EP/J017361/1). The research at Bath has been supported by the EPSRC (Grant No. EP/K016288/1 and EP/M009580/1). This work benefited from access to both the University of Bath's High Performance Computing Facility and ARCHER, the UK's national high-performance computing service, which is funded by the Offi ce of Science and Technology through EPSRC's High End Computing Programme (Grant No. EP/L000202).
- Mechanical, Electrical and Manufacturing Engineering