Control of optical bandgap energy and optical absorption coefficient by geometric parameters in sub-10nm silicon-nanodisc array structure

Mohd Fairuz Budiman, Weiguo Hu, Makoto Igarashi, Rikako Tsukamoto, Taiga Isoda, Kohei M. Itoh, Ichiro Yamashita, Akihiro Murayama, Yoshitaka Okada, Seiji Samukawa

Research output: Contribution to journalArticlepeer-review

33 Citations (Scopus)

Abstract

A sub-10nm, high-density, periodic silicon-nanodisc (Si-ND) array has been fabricated using a new top-down process, which involves a 2D array bio-template etching mask made of Listeria-Dps with a 4.5nm diameter iron oxide core and damage-free neutral-beam etching (Si-ND diameter: 6.4nm). An Si-ND array with an SiO 2 matrix demonstrated more controllable optical bandgap energy due to the fine tunability of the Si-ND thickness and diameter. Unlike the case of shrinking Si-ND thickness, the case of shrinking Si-ND diameter simultaneously increased the optical absorption coefficient and the optical bandgap energy. The optical absorption coefficient became higher due to the decrease in the center-to-center distance of NDs to enhance wavefunction coupling. This means that our 6nm diameter Si-ND structure can satisfy the strict requirements of optical bandgap energy control and high absorption coefficient for achieving realistic Si quantum dot solar cells.

Original languageEnglish
Article number065302
JournalNanotechnology
Volume23
Issue number6
DOIs
Publication statusPublished - 2012 Feb 17

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry(all)
  • Materials Science(all)
  • Mechanics of Materials
  • Mechanical Engineering
  • Electrical and Electronic Engineering

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