Damage-free top-down processes for fabricating two-dimensional arrays of 7 nm GaAs nanodiscs using bio-templates and neutral beam etching

• Published in: Nanotechnology Vol. 22; no. 36; pp. 365301 - 1-9
• Main Authors: Wang, Xuan-Yu, Huang, Chi-Hsien, Tsukamoto, Rikako, Mortemousque, Pierre-Andre, Itoh, Kohei M, Ohno, Yuzo, Samukawa, Seiji
• Format: Journal Article
• Language: English
• Published: England 07.09.2011
• Subjects: Animals; Arrays; Arsenicals - chemistry; Damage; Etching; Ferric Compounds - chemistry; Ferritin; Ferritins - chemistry; Ferritins - ultrastructure; Gallium - chemistry; Gallium arsenide; Gallium arsenides; Horses; Hydrochloric Acid - chemistry; Luminescent Measurements; Nanoparticles - chemistry; Nanoparticles - ultrastructure; Nanostructure; Nanotechnology - methods; Neutral beams; Oxygen - chemistry; Particle Size; Photoelectron Spectroscopy; Quantum Dots; Solutions; Spectroscopy, Fourier Transform Infrared; Surface Properties
• ISSN: 0957-4484; 1361-6528
• DOI: 10.1088/0957-4484/22/36/365301

The first damage-free top-down fabrication processes for a two-dimensional array of 7 nm GaAs nanodiscs was developed by using ferritin (a protein which includes a 7 nm diameter iron core) bio-templates and neutral beam etching. The photoluminescence of GaAs etched with a neutral beam clearly revealed that the processes could accomplish defect-free etching for GaAs. In the bio-template process, to remove the ferritin protein shell without thermal damage to the GaAs, we firstly developed an oxygen-radical treatment method with a low temperature of 280 °C. Then, the neutral beam etched the defect-free nanodisc structure of the GaAs using the iron core as an etching mask. As a result, a two-dimensional array of GaAs quantum dots with a diameter of ∼ 7 nm, a height of ∼ 10 nm, a high taper angle of 88° and a quantum dot density of more than 7 × 10(11) cm(-2) was successfully fabricated without causing any damage to the GaAs.