A high-performance InGaAs/GaAs vertical quantum dot infrared photodetector (QDIP) with combined barrier of quaternary In0.21Al 0.21Ga0.58As and GaAs was investigated in this study. A dominant long wavelength (∼10.2 m) response was observed from the device. The device demonstrates large responsivity (2.16 A/W) with narrow spectral-width (/ ∼0.14) and high detectivity (1.01 1011cm Hz1/2/W at 0.3 V) at 10.2 m at 77 K. In addition, the device has also produced a detectivity in the order of 6.4 1010cm Hz1/2/W at 100 K at a bias of 0.2 V, indicating its suitability for high-temperature operations. © 2011 American Institute of Physics.