Dark Current Measurement and Noise Correction Method for LWIR QWIP Detection System Based on Focal-Plane Temperature

Abstract

The performance of long-wave infrared (LWIR) quantum well (QWIP) detection systems is seriously affected by the dark current of the detectors. Tiny variations in the focal-plane temperature of the devices cause fluctuations in the dark current, which in turn generate temporal noise. It is difficult to measure the dark current accurately after the detector assembly is packaged. To address the above problems, a QWIP dark current measurement method based on focal-plane temperature is proposed, as well as a method to reduce dark current noise. First, the response model of the LWIR QWIP detection system was established, and the dark current model was introduced. Then, the detection system components were introduced, chiller calibration experiments were carried out, and the dark current values of the QWIP at different temperatures were measured by combining the system design and parameters. Next, the dark current noise correction method was proposed, the target data were collected, and experiments were carried out to correct them. Finally, after the calculation, the temporal noise was reduced by 57.69% after the correction, which is proof of a significant effect. This method can obtain the real-time dark current value by collecting the focal-plane temperature data, and reduce the dark current temporal noise (difficult to eliminate using conventional methods), which is beneficial for promoting the application of QWIPs in LWIR remote sensing detection.

Surface Plasmon Excitation as a Tool to Find Optimal Grating Parameters for Quantum well Infrared Photodetectors

“…Since, the n eff strongly depends on doping in the n + GaAs contact layers and n + GaAs QWs as well as on Al composition in the Al x Ga 1-x As barrier layer [11,12], changing these parameters in different QWIP designs demands different optimal grating periods. In general, the optimal grating parameters for a particular band of the QWIP can be obtained by performing detector characterizations at low temperature [13] where various processes such as several critical fabrication steps, packaging, bonding, low temperature measurement and their associated costs are involved. It is thus worthy to explore a simple cost effective technique to nd optimal gratings for the QWIP.…”