具有新型有源区的量子级联探测器(特邀)

Quantum Cascade Detectors with New Active Regions(Invited)

量子级联探测器是一种光伏型的子带间跃迁红外探测器,通过厚度渐变的啁啾量子阱中台阶状的子带分布,产生内建电场,使得有源区中的光生载流子定向输运,器件工作时无需外加偏压,避免了暗电流噪声的产生,能够实现室温长波红外响应。由于子带间跃迁吸收系数小、具有偏振选择性,量子级联探测器目前存在响应率低、对正入射响应无响应、探测率对温度敏感等问题。针对这些问题,本文介绍三种新型量子级联探测器有源区的设计,包括量子点/阱耦合、束缚-微带斜跃迁和小能量台阶有源区,在中波、长波和甚长波波段展现出优良的器件性能。

The quantum cascade detector is a photovoltaic inter-subband transition infrared detector.Through the cascading subband in the chirped quantum well with gradient thickness,a built-in electric field is generated to transport the photo-generated carriers in the active region.No bias voltage is applied when the device is working,thus avoiding the generation of dark current noise,and achieving room temperature long-wave infrared response.Due to the low absorption coefficient of the inter-subband transition and polarization selection rule,quantum cascade detectors currently have several problems such as low responsivity,no response to normal incidence,and temperature sensitivity of the detectivity.To address these issues,three quantum cascade detectors with new active regions are introduced,including quantum dot/well hybrid,bound-to-miniband diagonal transition,and mini-step transport active regions,exhibiting improved performance for mid,long,and very long wavelength infrared detection.