Surface Leakage Behaviors of 2.6 μm In0.83Ga0.17As Photodetectors as a Function of Mesa Etching Depth

Dark current behaviors of the 2.6 mu m cutoff wavelength In0.83Ga0.17As photodetectors are investigated as a function of the mesa etching depth. The total dark current monotonically declines from 2.0x10(-6) A/cm(2) to 8.3x10(-7) A/cm(2) at 180 K and -10 mV as the mesa etching depth decreases from 2.6 to 0.9 mu m. Meanwhile, an order of magnitude lower surface leakage current from 4.56 to 0.47 nA/cm, and a narrower statistical distribution are observed simultaneously. Moreover, the 300 K peak detectivity and quantum efficiency increase from 2.6x10(11) to 5.4x10(11) cmHz(1/2)/W and from 67.1% to 71.2%, respectively, as the mesa etching depth decreases from 2.6 to 0.9 mu m, benefit from the lateral carrier collection effect. These results suggest shallow mesa structures are indispensable towards surface leakage free In0.83Ga0.17As photodetectors.