An In_0.6Ga_0.4As/GaAs quantum dot infrared photodetector with operating temperature up to 260K

A high-sensitivity In_0.6Ga_0.4As/GaAs quantum-dot infrared photodetector (QDIP) with detection waveband in 6.7∼11.5 μm and operating temperature up to 260K under normal incident illumination has been demonstrated. The peak detection wavelength shifts from 7.6μm to 8.4μm when the temperature rises from 40 to 260K. The background limited performance (BLIP) detectivity (D*_BLIP) measured at V_b=1.5 V, T=77K and λ_p = 7.6 μm was found to be 1.25×10¹⁰ cm-Hz^1/2/W, with a corresponding responsivity of 0.22A/W. The high operating temperature is attributed to the very low dark current and long carrier lifetime in the quantum dots of this device. The results show that this QDIP can operate at high temperature without using the large band gap material such as AlGaAs or InGaP as blocking barrier to reduce the device dark current.