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 (/spl les/-1.0 V), the dark current density is as low as 10/sup -5/ A/cm/sup 2/ and the peak responsivity ranges from /spl sim/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/spl times/10/sup 9//spl les/D/sup */(cm/spl middot/Hz/sup 1/2//W)/spl les/10/sup 11/ for temperatures 100/spl les/T(K)/spl les/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.