Resonance-Enhanced Quantum Well Micropillar Array with Ultra-Narrow Bandwidth and Ultra-High Peak Quantum Efficiency

Infrared cameras with narrow-band detection capability are widely used for SF6 gas detection, which is an essential part of power equipment inspection. Narrow-band detection is usually achieved by a combination of quantum well infrared photodetectors (QWIPs) and narrow-band filters. Improving the quantum efficiency of QWIPs and reducing the detection bandwidth are important ways to improve camera performance. In this study, a back-incident-type device of quantum well micropillar array targeting at a 10.5 mu m central wavelength is designed and studied by three-dimensional simulation. The operating mechanism of the device was determined by investigating the effect of the device geometry on the quantum efficiency. The enhanced absorption capability of the device mainly comes from the Fabry-Perot resonance and the antireflection effect. The final device exhibits a remarkable peak quantum efficiency of 83% at 10.5 mu m and an ultra-narrow spectral bandwidth of 0.2 mu m. These excellent properties are achieved without an antireflective film and narrow-band filter, which can significantly improve the narrow-band capability and integration of the system; the dark current reduces to be 0.2762 times due to the low-duty cycle. These properties indicate that the structure of the quantum well micropillar array is of great significance to the development of QWIPs used in gas detection.