A Novel Method Based on Oblique Depositions to Fabricate Quantum Dot Arrays

We propose a novel method to fabricate quantum dot (QD) arrays, utilizing nanometer-sized columnar structures of obliquely deposited thin films arising from the self-shadowing effect. We found that columns consisting of alternating arrays of QDs and barriers can be formed by means of alternate oblique depositions of the semiconductor and the dielectric onto rotating substrates. The deposition conditions were optimized by both computer simulations and experiments. The proposed method was demonstrated by depositing Si (QDs) and SiO₂ (barriers) alternately onto rotating Si wafers or SiO₂ glass plates at a deposition angle of 85deg, followed by annealing at 1000 degC to promote crystallization. The formation of crystalline Si QD arrays was confirmed by scanning electron microscopy, Raman scattering, and photoluminescence. This method can be utilized for various materials and has a significant advantage over the self-assembly of QDs based on the Stranski-Krastanow growth mode, and other methods, as these limit the materials that can be grown