Low-noise, low-dark-current GaN diodes for UV detectors

Peter W. Deelman, Robert N. Bicknell-Tassius, Sergey Nikishin, Henryk Temkin

Research output: Contribution to journalArticlepeer-review


We report mesa-isolated Schottky barrier photodetectors fabricated on n-GaN. Single-element detectors were constructed from nitride epilayers grown by gas source molecular beam epitaxy (GSMBE) on Si(111). Chlorine-based reactive ion etching was used to form two-level mesas. The detectors were front-illuminated through 100 Å Pd semitransparent Schottky contacts on the upper mesas; ohmic contact on the lower mesas was made using standard Ti/Al/Ti/Au metallurgy. Silicon dioxide grown by plasma-enhanced chemical vapor deposition provided both surface passivation and electrical isolation. The dark current of an 86 × 86 μm2 single-element detector is 2.10 × 10-8 A/cm2 at -2 V bias, and the zero-bias noise power density at 1 Hz is as low as 9 × 10-29 A2/Hz. In addition, we present preliminary results for p-n diodes fabricated from epilayers grown on sapphire. The dark current of a 50 × 50 μm2 single-element detector is 1.6 × 10-6 A/cm2 at -2 V bias.

Original languageEnglish
Pages (from-to)G11.27.1-G11.27.6
JournalMaterials Research Society Symposium - Proceedings
StatePublished - 2001


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