Analysis of dark current and spectral response mechanisms for Si-based block-impurity-band detectors operating at terahertz regime

摘要

Si-based blocked-impurity-band (BIB) detector with enhanced terahertz-photo-detection capability has been realized, and an accurate physics-based numerical model has been constructed. The simulation is in good agreement with the experiment. Based on experimental measurements and numerical simulations, dark current and spectral response mechanisms in Si-based BIB detectors are investigated. Our results reveal that the dark current is dominated by the impurity-band conductance when the temperature is below a critical value, while above this critical value, the dark current will be dominated by the conduction-band conductance instead. The dependences of dark current and peak responsivity on the thickness of the blocking layer are quantitatively studied. It is demonstrated that a trade-off between dark current and peak responsivity has to be made for the optimal thickness of the blocking layer.