Characteristics of back-illuminated visible-blind UV photodetector based on AlxGa1-xN p-i-n photodiodes

Kyong Seok Chae, Dong Wook Kim, Bong Soo Kim, Sung Jin Som, In Hwan Lee, Cheul Ro Lee

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)


In this work, we reported the growth, fabrication and characterization of an AlxGa1-xN heteroepitaxial back-illuminated visible-blind UV photodetector designed for flip-chip mounting. This device was grown on one side of a polished sapphire substrate using a low-temperature AlN buffer layer created by six-pocket multi-wafer system metalorganic chemical vapor deposition (MOCVD) with a vertical reactor. In order to obtain the wavelength of the visible-blind region, the AlxGa1- xN layer was grown under various conditions of growth time and gas flow rate, after optimizing the AlN buffer layer. This device consisted of a 1.3 μm thick Al0.15Ga0.85N "window layer", a 0.16 μm thick Al0.08Ga0.92N i-layer, a 0.46 μm thick Al0.08Ga0.92N p-layer, a 0.1 μm thick GaN p-layer, followed by a 30 nm GaN:Mg p+-contact layer. All of the device processing was completed using standard semiconductor processing techniques that included photolithography, metallization and etching. In this device, the zero-bias peak responsivity was found around 0.052 A/W at 340 nm, corresponding to an external quantum efficiency of 19%. The rise and fall time of the photoresponse was 20.8 ns. Moreover, this device exhibits a low dark current density of 17 pA/cm2 at zero-bias.

Original languageEnglish
Pages (from-to)367-373
Number of pages7
JournalJournal of Crystal Growth
Issue number3-4
Publication statusPublished - 2005 Apr 1
Externally publishedYes


  • A1. Heat resolution X-ray diffraction
  • A2. Growth from high temperature solutions
  • A3. Metalorganic chemical vapor deposition
  • B1. Gallium compounds
  • B2. Semiconducting III-V materials
  • B3. Hetero-junction semiconductor devices

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Inorganic Chemistry
  • Materials Chemistry


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