Spectral modulation of blocked-impurity-band hybrid structure terahertz detector

This paper is a study composed of experiment and simulation. We conceived a blocked-impurity-band hybrid structure for terahertz radiation detection. The modulation effect of sub-wavelength metal grating on light absorption has been analyzed theoretically. The optical absorption and spectral response of sub-wavelength metal grating/Si:P blocked-impurity-band hybrid structure detectors are simulated by Finite Difference-Time Domain solution. Compared with the detector without grating structure, the hybrid structure detectors have the effects of selective absorption amplification and filtering. Moreover, the fabrication and experimental details of the hybrid structure detectors have been investigated. The results show that the response peak wavelength 18.3 mu m of the Si:P blocked-impurity-band detector has been modulated to 14.3, 22.8, 28.2, and 33.1 mu m (& SIM;9.1 THz). Especially, about 140% absorption enhancement is achieved at the response peak wavelength 28.2 mu m. Furthermore, the modulation mechanisms of spectral responses on operation bias voltages and temperatures have also been studied. This study provided an effective method to modulate the spectral response of the Si:P BIB detector.