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

Highly compact In₂O₃ nanodots with uniform size were synthesized by a novel approach via direct annealing of Ni/InAs samples at temperatures over 250 °C. The In₂O₃ 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 ₂O₃ 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 In₂O₃ nanodots, can be observed. The peaks originate from radioactive recombination centers such as oxygen vacancies or indium interstitials inside In₂O₃ 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 ₂O₃ nanodots at a specific position. Applications for precisely locating optoelectronic nanodevices in combination with electronic nanodevices are envisioned.