Very low excess noise Al0.75Ga0.25As0.56Sb0.44 avalanche photodiode

Xiao Jin, Harry I. J. Lewis, Xin Yi, Shiyu Xie, Baolai Liang, Qingyu Tian, Diana L. Huffaker, Chee Hing Tan, John P. R. David

Research output: Contribution to journalArticlepeer-review

2 Citations (Scopus)
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AlxGa1-xAsySb1-y grown lattice-matched to InP has attracted significant research interest as a material for low noise, high sensitivity avalanche photodiodes (APDs) due to its very dissimilar electron and hole ionization coefficients, especially at low electric fields. All work reported to date has been on Al concentrations of x = 0.85 or higher. This work demonstrates that much lower excess noise (F = 2.4) at a very high multiplication of 90 can be obtained in thick Al0.75Ga0.25As0.56Sb0.44 grown on InP substrates. This is the lowest excess noise that has been reported in any III-V APD operating at room temperature. The impact ionization coefficients for both electrons and holes are determined over a wide electric field range (up to 650 kV/cm) from avalanche multiplication measurements undertaken on complementary p-i-n and n-i-p diode structures. While these ionization coefficients can fit the experimental multiplication over three orders of magnitude, the measured excess noise is significantly lower than that expected from the β/α ratio and the conventional local McIntyre noise theory. These results are of importance not just for the design of APDs but other high field devices, such as transistors using this material.
Original languageEnglish
Pages (from-to)33141-33149
Number of pages9
JournalOptics Express
Issue number20
Early online date19 Sept 2023
Publication statusPublished - 25 Sept 2023


  • Atomic and Molecular Physics, and Optics


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