The thickness effect of p-AlGaN blocking layer in UV-A bandpass photodetectors

C. K. Wang*, T. K. Ko, C. S. Chang, S. J. Chang, Y. K. Su, T. C. Wen, Cheng-Huang Kuo, Y. Z. Chiou

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

12 Scopus citations


By means of 60-, 150-, and 300-nm-thick blocking p-Al0.1 Ga0.9N layers, we have successfully achieved high performance on nitride-based p-i-n bandpass photodetectors. The peak responsivities were estimated to be 0.131, 0.129, and 0.13 A/W at 354, 357, and 356 nm for 60-, 150-, and 300-nm-thick p-Al0.1Ga0.9N blocking layer, respectively, corresponding to a quantum efficiency of around 46%. Moreover, spectral responsivity for 300-nm-thick blocking p-Al0.1Ga0.9N layer shows the narrowest bandpass characteristics from 320 to 365 nm (UV-A region). The photodetectors exhibit a 20-V break-down voltage and a small dark current of around 3 pA at 5-V reverse bias. For our 330 × 330 μm2 devices given bias of 0 V, the detectivity D* limited by Johnson noise are calculated to be 3.43 × 1013 6.77 × 1013, and 8.22 × 1013 cm - Hz0.5 W-1, respectively.

Original languageEnglish
Pages (from-to)2161-2163
Number of pages3
JournalIEEE Photonics Technology Letters
Issue number10
StatePublished - 1 Oct 2005


  • AIGaN-GaN
  • Band-pass
  • Noise
  • P-i-n
  • Photodetector


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