Abstract
We experimentally demonstrate an amorphous ternary metal oxide of Fe, Tb, and Dy exhibiting high electronic conductivity, Hall mobility, and optical transparency driven by partly filled d- and f-subshells.
| Original language | English |
|---|---|
| Article number | JTh2A.87 |
| Journal | Optics InfoBase Conference Papers |
| State | Published - 2016 |
| Event | CLEO: Applications and Technology, CLEO AT 2016 - San Jose, United States Duration: Jun 5 2016 → Jun 10 2016 |
Funding
This work was primarily supported by ARO grant W911NF-13-1-0428, and a Science Alliance JDRD grant U013960010. Portions of this work were performed at Oak Ridge National Laboratory, operated by UT-Battelle for the U.S. Department of Energy. The authors B.L. and R.P. recognize support from the Laboratory Directed Research and Development program. XPS measurements were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility. Temperature dependent four point probe measurements were performed in the Van der Pauw geometry in order to characterize the dependence of the conductivity and Hall mobility on available growth conditions. The measured mobility was 32±4 cm2/Vs across varying film thicknesses and the n-type conductivity ranged from 5 x 103 – 5 x 104 S/m, orders of magnitude higher than the mobility and conductivity in the constituent oxides. The exponential dependence of conductivity on temperature provided further confirmation that this TCO is in fact a semiconducting film, and not a result of distributed metallic nanoparticles. The conductivity did drop by a factor of 3 for N2 annealing and by a factor of 17 for O2 annealing, but even in the annealed films, the mobility and conductivity remained orders of magnitude larger than in the constituent metal oxides. Ongoing experiments have shown preliminary evidence of a strong Tb-induced photoluminescence peak in this TCO, potentially enabling novel optoelectronic applications. Initial research into this material shows transparency and conductivity competitive with currently used TCOs, but in a platform that must rely on fundamentally different physics. Previously reported TCOs based on ternary amorphous oxides have relied on the overlap of ns levels involved in metal cation bonding, and have utilized the ternary system as a mechanism to stabilize the amorphous microstructure of an existing conductive oxide. Because the s-subshells of Fe, Tb and Dy are unlikely to contribute to the conduction band of the composite oxide, the high mobility seen here must have a profoundly different origin. Current work is aimed at unraveling the physics behind this novel TCO based on the hypothesis that a strong interaction between Fe 5d and Lanthanide 4f levels could drive the anomalous conductivity. This work was primarily supported by ARO grant W911NF-13-1-0428, and a Science Alliance JDRD grant U013960010. Portions of this work were performed at Oak Ridge National Laboratory, operated by UT-Battelle for the U.S. Department of Energy. The authors B.L. and R.P. recognize support from the Laboratory Directed Research and Development program. XPS measurements were conducted at the Center for Nanophase Materials Sciences, which is a DOE Office of Science User Facility.
| Funders | Funder number |
|---|---|
| Science Alliance JDRD | U013960010 |
| U.S. Department of Energy | |
| Army Research Office | W911NF-13-1-0428 |
| Office of Science | |
| Oak Ridge National Laboratory | |
| Laboratory Directed Research and Development | |
| UT-Battelle |