Wide spectrum terahertz quantum well photodetector

A 45 degrees-incident facet wide-spectrum terahertz (THz) quantum well photodetector (QWP) is presented. It peaks at similar to 2.0 THz with a full width at half maximum of 3.0 THz. The response frequency covers 1.5-7.6 and 8.8-20.3 THz. It has the highest responsivity of 0.18 AW(-1) and a best specific detectivity of 3.5 x 10(10) cm Hz(0.5) W-1. It is an initial attempt to achieve a wide spectrum THz QWP below 3.0 THz, which has promising applications in THz radar or THz imaging.