Piezo-phototronic effect on electroluminescence properties of p-type GaN thin films

Youfan Hu, Yan Zhang, Long Lin, Yong Ding, Guang Zhu, Zhong Lin Wang

Research output: Journal PublicationArticlepeer-review

52 Citations (Scopus)


We present that the electroluminescence (EL) properties of Mg-doped p-type GaN thin films can be tuned by the piezo-phototronic effect via adjusting the minority carrier injection efficiency at the metal-semiconductor (M-S) interface by strain induced polarization charges. The device is a metal-semiconductor- metal structure of indium tin oxide (ITO)-GaN-ITO. Under different straining conditions, the changing trend of the transport properties of GaN films can be divided into two types, corresponding to the different c-axis orientations of the films. An extreme value was observed for the integral EL intensity under certain applied strain due to the adjusted minority carrier injection efficiency by piezoelectric charges introduced at the M-S interface. The external quantum efficiency of the blue EL at 430 nm was changed by 5.84% under different straining conditions, which is 1 order of magnitude larger than the change of the green peak at 540 nm. The results indicate that the piezo-phototronic effect has a larger impact on the shallow acceptor states related EL process than on the one related to the deep acceptor states in p-type GaN films. This study has great significance on the practical applications of GaN in optoelectronic devices under a working environment where mechanical deformation is unavoidable such as for flexible/printable light emitting diodes.

Original languageEnglish
Pages (from-to)3851-3856
Number of pages6
JournalNano Letters
Issue number7
Publication statusPublished - 11 Jul 2012
Externally publishedYes


  • GaN film
  • electroluminescence
  • piezo-phototronic effect

ASJC Scopus subject areas

  • Bioengineering
  • Chemistry (all)
  • Materials Science (all)
  • Condensed Matter Physics
  • Mechanical Engineering


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