Jump to main content
Jump to site search

Issue 24, 2014
Previous Article Next Article

Pseudo-direct bandgap transitions in silicon nanocrystals: effects on optoelectronics and thermoelectrics

Author affiliations

Abstract

While silicon nanostructures are extensively used in electronics, the indirect bandgap of silicon poses challenges for optoelectronic applications like photovoltaics and light emitting diodes (LEDs). Here, we show that size-dependent pseudo-direct bandgap transitions in silicon nanocrystals dominate the interactions between (photoexcited) charge carriers and phonons, and hence the optoelectronic properties of silicon nanocrystals. Direct measurements of the electronic density of states (DOS) for different sized silicon nanocrystals reveal that these pseudo-direct transitions, likely arising from the nanocrystal surface, can couple with the quantum-confined silicon states. Moreover, we demonstrate that since these transitions determine the interactions of charge carriers with phonons, they change the light emission, absorption, charge carrier diffusion and phonon drag (Seebeck coefficient) in nanoscaled silicon semiconductors. Therefore, these results can have important implications for the design of optoelectronics and thermoelectric devices based on nanostructured silicon.

Graphical abstract: Pseudo-direct bandgap transitions in silicon nanocrystals: effects on optoelectronics and thermoelectrics

Back to tab navigation

Supplementary files

Publication details

The article was received on 14 Aug 2014, accepted on 12 Oct 2014 and first published on 13 Oct 2014


Article type: Communication
DOI: 10.1039/C4NR04688A
Citation: Nanoscale, 2014,6, 14643-14647
  •   Request permissions

    Pseudo-direct bandgap transitions in silicon nanocrystals: effects on optoelectronics and thermoelectrics

    V. Singh, Y. Yu, Qi-C. Sun, B. Korgel and P. Nagpal, Nanoscale, 2014, 6, 14643
    DOI: 10.1039/C4NR04688A

Search articles by author

Spotlight

Advertisements