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 · Hz1/2/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.
Chakrabarti, S; Stiff-Roberts, AD; Bhattacharya, P; Gunapala, S; Bandara, S; Rafol, SB; Kennerly, SW
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