Crack-free AlGaN for solar-blind focal plane arrays through reduced area epitaxy

E. Cicek, R. McClintock, Z. Vashaei, Y. Zhang, S. Gautier, C. Y. Cho, M. Razeghi*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


We report on crack reduction for solar-blind ultraviolet detectors via the use of a reduced area epitaxy (RAE) method to regrow on patterned AlN templates. With the RAE method, a pre-deposited AlN template is patterned into isolated mesas in order to reduce the formation of cracks in the subsequently grown high Al-content AlxGa1-xN structure. By restricting the lateral dimensions of the epitaxial growth area, the biaxial strain is relaxed by the edges of the patterned squares, which resulted in ∼97% of the pixels being crack-free. After successful implementation of RAE method, we studied the optical characteristics, the external quantum efficiency, and responsivity of average pixel-sized detectors of the patterned sample increased from 38% and 86.2 mA/W to 57% and 129.4 mA/W, respectively, as the reverse bias is increased from 0 V to 5 V. Finally, we discussed the possibility of extending this approach for focal plane array, where crack-free large area material is necessary for high quality imaging.

Original languageEnglish (US)
Article number051102
JournalApplied Physics Letters
Issue number5
StatePublished - Feb 4 2013

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)


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