Kinetic growth of self-formed In2O3 nanodots via phase segregation: Ni/InAs system

Highly compact In(2)O(3) nanodots with uniform size were synthesized by a novel approach via direct annealing of Ni/InAs samples at temperatures over 250 °C. The In(2)O(3) nanodots were formed by solid diffusion between nickel and indium arsenide (InAs) and phase segregation via a catalyst-assisted kinetic process. By controlling the annealing time and ambient conditions, the size and density of In(2)O(3) nanodots can be controlled. From photoluminescence (PL) measurements, two distinct peaks located at ∼430 and ∼850 nm, corresponding to 2.9 and 1.5 eV for In(2)O(3) nanodots, can be observed. The peaks originate from radioactive recombination centers such as oxygen vacancies or indium interstitials inside In(2)O(3) nanodots. The periodic array of Ni microdiscs with diameters and interdisc spacing of ∼5 and ∼10 μm on InAs substrate surface prepared by a photolithography process demonstrated the precise control of In(2)O(3) nanodots at a specific position. Applications for precisely locating optoelectronic nanodevices in combination with electronic nanodevices are envisioned.