Ultrafast relaxation of hot phonons in graphene-hBN heterostructures

Dheeraj Golla, Alexandra Brasington, Brian J Leroy, Arvinder Singh Sandhu

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

Fast carrier cooling is important for high power graphene based devices. Strongly coupled optical phonons play a major role in the relaxation of photoexcited carriers in graphene. Heterostructures of graphene and hexagonal boron nitride (hBN) have shown exceptional mobility and high saturation current, which makes them ideal for applications, but the effect of the hBN substrate on carrier cooling mechanisms is not understood. We track the cooling of hot photo-excited carriers in graphene-hBN heterostructures using ultrafast pump-probe spectroscopy. We find that the carriers cool down four times faster in the case of graphene on hBN than on a silicon oxide substrate thus overcoming the hot phonon bottleneck that plagues cooling in graphene devices.

Original languageEnglish (US)
Article number056101
JournalAPL Materials
Volume5
Issue number5
DOIs
Publication statusPublished - May 1 2017

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ASJC Scopus subject areas

  • Materials Science(all)
  • Engineering(all)

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