A GaAsSb/AlGaAsSb Avalanche Photodiode With a Very Small Temperature Coefficient of Breakdown Voltage

Avalanche photodiodes (APDs) made with the material AlGaAsSb (lattice-matched to InP) exhibit very low excess noise characteristics. We demonstrate a Separate Absorption and Multiplication APD (SAM-APD) incorporating a GaAs0.52Sb0.48 (GaAsSb) absorption region and an Al0.85Ga0.15As0.56Sb0.44 (AlGaAsSb) avalanche region. Our GaAsSb/AlGaAsSb SAM-APD exhibits a cut-off wavelength of 1.70 mu m at room temperature and a responsivity of 0.39 A/W at 1.55 mu m wavelength (with no antireflection coating). Temperature dependence of the breakdown voltage was obtained from avalanche gain data from multiple devices operated at 77 to 295 K. This produced a temperature coefficient of breakdown voltage of 4.31 +/- 0.33 mV/K, a factor of 10 and 5 smaller than values for comparable InP and InAlAs SAM-APDs. The very small temperature coefficient of this work is consistent with the extremely weak temperature dependence of avalanche breakdown previously observed in AlGaAsSb diodes.

Automated summary

Avalanche photodiodes (APDs) made with AlGaAsSb exhibit excellent noise characteristics. The SAM-APD incorporating GaAsSb absorption region and AlGaAsSb avalanche region shows a cutoff wavelength of 1.70 μm and a responsivity of 0.39 A/W at 1.55 μm wavelength. The temperature dependence of the breakdown voltage is significantly smaller compared to InP and InAlAs SAM-APDs.