A flexible method for depositing dense nanocrystal thin films: Impaction of germanium nanocrystals

Zachary Holman, U. R. Kortshagen

Research output: Contribution to journalArticle

40 Citations (Scopus)

Abstract

Nanomaterials are exciting candidates for use in new optical and electronic devices ranging from solar cells to gas sensors. However, to reach their full potential, nanomaterials must be deposited as dense thin films on flexible substrates using inexpensive processing technologies such as roll-to-roll printing. We report a new, flexible technique for depositing aerosolized nanocrystals that lends itself to roll-to-roll processes. Germanium nanocrystals produced in a plasma are accelerated through a slit orifice by a supersonic gas jet and are impacted onto a translated substrate. A uniform nanocrystal film is quickly deposited over large areas, and features as small as 2 μm can then be patterned using conventional lift-off photolithography. The density of a deposited film depends on the pressures upstream and downstream of the orifice, their ratio, and the distance between the orifice and the substrate. Nanocrystal film densities exceeding 50% of the density of bulk germanium are routinely achieved with several sizes of nanocrystals, approaching the theoretical limit for randomly packed spheres. A simple model is presented that shows that the calculated nanocrystal velocity upon impaction is strongly correlated with the resulting film density.

Original languageEnglish (US)
Article number335302
JournalNanotechnology
Volume21
Issue number33
DOIs
StatePublished - Aug 20 2010
Externally publishedYes

Fingerprint

Germanium
Nanocrystals
Thin films
Orifices
Nanostructured materials
Substrates
Photolithography
Chemical sensors
Printing
Solar cells
Gases
Plasmas
Processing

ASJC Scopus subject areas

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

Cite this

A flexible method for depositing dense nanocrystal thin films : Impaction of germanium nanocrystals. / Holman, Zachary; Kortshagen, U. R.

In: Nanotechnology, Vol. 21, No. 33, 335302, 20.08.2010.

Research output: Contribution to journalArticle

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