Quantum confinement in mixed phase silicon thin films grown by co-deposition plasma processing

J. D. Fields, S. McMurray, L. R. Wienkes, J. Trask, C. Anderson, P. L. Miller, B. J. Simonds, J. Kakalios, U. Kortshagen, M. T. Lusk, R. T. Collins, P. C. Taylor

Research output: Contribution to journalArticlepeer-review

7 Scopus citations

Abstract

Mixed phase, hydrogenated amorphous and nanocrystalline silicon thin films grown by co-deposition (nanocrystals and amorphous material deposited sequentially in the same vacuum system) demonstrate pronounced quantum confinement effects. Based on photoluminescence measurements of co-deposited samples, we find evidence that the optical gap of nanocrystals embedded in hydrogenated amorphous silicon is increased to energies exceeding bulk crystalline silicon values - at least as high as 1.35 eV. The broad spectrum of emission of the nanocrystals is attributed to the size distribution and local fluctuations in matrix hydrogenation. The temperature dependence of this PL suggests that these nanocrystals possess fewer defects than those grown by conventional plasma enhanced chemical vapor deposition methods. Interactions between electronic states in nanocrystals and localized states in amorphous silicon matrix tissues are discussed in terms of their role in determining the strength of the quantum confinement potential.

Original languageEnglish (US)
Pages (from-to)7-12
Number of pages6
JournalSolar Energy Materials and Solar Cells
Volume129
DOIs
StatePublished - Oct 2014

Keywords

  • Nanocrystalline silicon
  • Nanostructures
  • Photoluminescence
  • Photovoltaics
  • Quantum confinement

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