Self-regulated charge transfer and band tilt in nm-scale polar GaN films

M. H. Tsai, Sandwip Dey

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Using first-principles calculation for the electronic structures of nm-scale [0001] GaN freestanding films, it is found that the Ga-terminated surface (SGa) has a positive electrostatic potential, while the N-terminated surface has a negative electrostatic potential (SN), so that the energy bands tilt upwards from SGa to SN. Additionally, it is determined that an intrinsic self-regulated charge transfer across the film limits the electrostatic potential difference across the film, which renders the local conduction band energy minimum at SGa approximately equal to the local valence band energy maximum at SN. This effect is found to occur in films thicker than ∼4 nm. If the dangling-bond/surface states at both SGa and SN are passivated by pseudo-hydrogen atoms, the tilt of energy bands is similar, though the cross-film potential is reduced due to the extra H5/4-Ga and N-H3/4 dipole layers.

Original languageEnglish (US)
Pages (from-to)125-130
Number of pages6
JournalEPJ Applied Physics
Volume36
Issue number2
DOIs
StatePublished - Nov 2006

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Charge transfer
charge transfer
energy bands
Electrostatics
electrostatics
Band structure
Dangling bonds
Surface states
Valence bands
Conduction bands
Thick films
thick films
Electronic structure
Hydrogen
hydrogen atoms
conduction bands
dipoles
electronic structure
valence
Atoms

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

Cite this

Self-regulated charge transfer and band tilt in nm-scale polar GaN films. / Tsai, M. H.; Dey, Sandwip.

In: EPJ Applied Physics, Vol. 36, No. 2, 11.2006, p. 125-130.

Research output: Contribution to journalArticle

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