Ordering of high-quality InAs quantum dots on defect-free nanoholes

We demonstrate a promising way for the fabrication of high-quality InAs quantum dot (QD) arrays by combining atomic force microscope (AFM) tip-induced nano-oxidation, atomic-hydrogen etching/cleaning (AHE/C), and droplet epitaxy method. The highly aligned defect-free nanoholes as nucleation sites were fabricated by using AFM tip-induced nano-oxidation and subsequent AHE/C. Using the droplet epitaxy on the artificially patterned nanoholes, we fabricated laterally arrayed InAs QDs with an interdot distance of 100 nm. The photoluminescence from the InAs QD arrays showed strong emission at 1.22 eV, even though the processed interface directly faced the base of the InAs QDs, indicating that the process can reduce the physical and chemical defects/contaminants at the nanoholes and interface.