低占空比红外增强吸收的量子阱微柱阵列

Quantum well micropillar arrays with low filling factor for enhanced infrared absorption

为了提高长波红外量子阱探测器的光耦合效率和信噪比,以8.7μm为中心波长,设计和制备了量子阱亚波长微柱阵列结构。与已经报道的金属或介质微腔结构不同,本文的微柱结构有源区包含50周期的量子阱/垒层,结合低至0.18的占空比,可望在增强吸收的同时显著抑制暗电流。红外光谱测量验证了制备的微柱阵列在8~9μm波段8%以内的低反射率特征,从而为高工作温度、高信噪比的长波红外探测提供了新方案。

To improve the efficiency of optical coupling and the signal-to-noise ratio of long wavelength quantum well infrared detector(LW-QWIP),we designed and fabricated a quantum well subwavelength micropillar arrays structure targeting at 8.7μm central wavelength.Different from the reported metal or dielectric microcavity structures,each pillar contains 50 periods of quantum wells and barriers,which combined with the filling factor lower than 0.18 is expected to considerably suppress the dark current while enhancing the efficiency of light absorption.Infrared spectrum measurement discloses that the micropillar arrays reflect only 8%in the wavelength range of 8~9μm.Our study offers a practical scheme for sensitive infrared detection at high operation temperature.