Highly tunable charge transport in layer-by-layer assembled graphene transistors

Hyunmin Hwang, Piljae Joo, Moon Sung Kang, Gukmoon Ahn, Joong Tark Han, Byeong Su Kim, Jeong Ho Cho

Research output: Contribution to journalArticlepeer-review

80 Citations (Scopus)


We demonstrate a controlled, systematic method to tune the charge transport in graphene field-effect transistors based on alternating layer-by-layer assembly of positively and negatively charged graphene oxide followed by thermal reduction. Surprisingly, tuning the number of bilayers of thermally reduced graphene oxide multilayer films allowed achieving either ambipolar or unipolar (both n- and p-type) transport in graphene transistors. On the basis of X-ray photoemission spectroscopy, Raman spectroscopy, time-of-flight secondary ion mass spectrometry, and temperature-dependent charge transport measurements, we found that nitrogen atoms from the functional groups of positively charged graphene oxide are incorporated into the reduced graphene oxide films and substitute carbon atoms during the thermal reduction. This nitrogen-doping process occurs in different degrees for graphene multilayers with varying numbers of bilayers and thereby results in the interesting transition in the electrical behavior in graphene multilayer transistors. We believe that such a versatile method to control the charge transport in graphene multilayers will further promote their applications in solution-processable electronic devices based on graphene.

Original languageEnglish
Pages (from-to)2432-2440
Number of pages9
JournalACS Nano
Issue number3
Publication statusPublished - 2012 Mar 27

All Science Journal Classification (ASJC) codes

  • Materials Science(all)
  • Engineering(all)
  • Physics and Astronomy(all)


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