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 (≤-1.0 V), the dark current density is as low as 10^-5 A/cm² and the peak responsivity ranges from ∼0.1 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 6×10⁹≤D^*(cm·Hz¹2//W)≤10¹¹ for temperatures 100≤T(K)≤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.