High-temperature operation of InAs-GaAs quantum-dot infrared photodetectors with large responsivity and detectivity

We have optimized the growth of multiple (40-70) layers of self-organized InAs quantum dots separated by GaAs barrier layers in order to enhance the absorption of quantum-dot infrared photodetectors (QDIPs). In devices with 70 quantum-dot layers, at relatively large operating biases (less than or equal to -1.0 V), the dark current density is as low as 10(-5) A/cm(2) and the peak responsivity ranges from similar to0.1 to 0.3 A/W for temperatures T = 150 K - 175 K. The peak detectivity corresponding to these low dark currents and high responsivities varies in the range 6 x 10(9) less than or equal to D-* (cm . Hz(1/2)/W) less than or equal to 10(11) for temperatures 100 less than or equal to T(K) less than or equal to 200. These performance characteristics represent the state-of-the-art for QDIPs and indicate that this device heterostructure is appropriate for incorporation into focal plane arrays.