Impact of the Structural Parameters on the Photoresponse of Terahertz Blocked-Impurity-Band Detectors with Planar Structure

We fabricate germanium-based blocked-impurity-band (BIB) terahertz detectors with the same planar structure but different structural parameters. The photoresponse waveband range is about 40-130 μm. The best detectivity of these detectors reaches as high as 1.3 × 1013 Jones at 2.6 V and 4 K. The impact of the structural parameters, including the length of the absorbing layer and blocking layer (BL) on the performance of detectors, is investigated. It is concluded that there is an optimum BL length, enabling the fabricated BIB detectors to achieve the highest sensitivity. This work highlights the importance of the optimized structural parameters and their influence on the performance of the detectors.