Dark current in antimony-based mid-infrared interband cascade infrared photodetectors

• This paper presents the detailed electrical performance of high performance MWIR interband cascade (IC) photodetectors.
• Our results suggest that the dark current in MWIR IC detectors at lower temperatures are dominated by tunneling processes.
• At higher temperatures, the dark current in IC detectors is dominated by diffusion process.

The quantum-engineered interband cascade (IC) photodetector is a new type of infrared detectors with many unique and highly desirable features. The multi-stage design allows much flexibility in device optimization for different application environment, such as operation temperature, irradiance level, and possibly high-speed and fast frame-rate application scenarios. Many other distinctive features, such as excellent photo-carrier extraction and photovoltaic (zero-bias) operations, are also very attractive for high performance infrared imaging applications. In this paper, we report our experimental investigation on the dark current mechanisms in mid-wave infrared (MWIR) InAs/GaSb type-II superlattices based IC photodetectors. The electrical performance of MWIR IC detectors with several different designs are presented in detail. The dark current density in the MWIR IC detectors is as low as 4.26 × 10−8 A/cm2 (1.44 × 10−3 A/cm2) at −10 mV, with Johnson-limited D∗ of 9.11 × 1011 cm Hz1/2/W (1.58 × 109 cm Hz1/2/W) at 140 K (room temperature) and 3.6 μm. Our results indicate that the dominating dark current in IC detectors is from tunneling components at lower temperatures, and changes to diffusion current at higher operating temperatures. Furthermore, our effort also shows that the dark current performance in IC devices can be improved substantially by refining the device design and implementations.