1 research outputs found
<i>In Situ</i> Chemical Modification of Schottky Barrier in Solution-Processed Zinc Tin Oxide Diode
Here
we present a novel <i>in situ</i> chemical modification
process to form vertical Schottky diodes using palladium (Pd) rectifying
bottom contacts, amorphous zinc tin oxide (Zn–Sn–O)
semiconductor made via acetate-based solution process, and molybdenum
top ohmic contacts. Using X-ray photoelectron spectroscopy depth profiling,
we show that oxygen plasma treatment of Pd creates a PdO<sub><i>x</i></sub> interface layer, which is then reduced back to metallic
Pd by <i>in situ</i> reactions during Zn–Sn–O
film annealing. The plasma treatment ensures an oxygen-rich environment
in the semiconductor near the Schottky barrier, reducing the level
of oxygen-deficiency-related defects and improving the rectifying
contact. Using this process, we achieve diodes with high forward current
density exceeding 10<sup>3</sup>A cm<sup>–2</sup> at 1 V, rectification
ratios of >10<sup>2</sup>, and ideality factors of around 1.9.
The measured diode current–voltage characteristics are compared
to numerical simulations of thermionic field emission with sub-bandgap
states in the semiconductor, which we attribute to spatial variations
in metal stoichiometry of amorphous Zn–Sn–O. To the
best of our knowledge, this is the first demonstration of vertical
Schottky diodes using solution-processed amorphous metal oxide semiconductor.
Furthermore, the <i>in situ</i> chemical modification method
developed here can be adapted to tune interface properties in many
other oxide devices