A study of low-bias photocurrent gradient of avalanche photodiodes

Shuling Wang, Rubin Sidhu, Gauri Karve, Feng Ma, Xiaowei Li, Xiao Guang Zheng, Jeffrey Byron Hurst, Xiaguang Sun, Ning Li, Archie L. Holmes, Joe C. Campbell

Research output: Contribution to journalArticlepeer-review

5 Scopus citations


We present a study of the photo-response of avalanche photodiodes (APDs) under low reverse bias at unity gain. Some wafers exhibit a linear increase of photocurrent as a function of bias voltage; the "slope" of this linear current-voltage (I-V) curve has been examined under different illumination conditions, fabrication procedures and growth conditions. The observed characteristics are explained in terms of the extension of the depletion region edge toward the surface. An analytical model, based on minority drift-diffusion and current continuity equations, provides good fits to the experimental results for small (∼ 0.1 μm) "effective diffusion lengths".

Original languageEnglish (US)
Pages (from-to)2107-2113
Number of pages7
JournalIEEE Transactions on Electron Devices
Issue number12
StatePublished - Dec 2002

All Science Journal Classification (ASJC) codes

  • Electronic, Optical and Magnetic Materials
  • Electrical and Electronic Engineering

Cite this