Improved optical properties and detectivity of an uncooled silicon carbide mid-wave infrared optical detector with increased dopant concentration
Abbreviated Journal Title
infrared detector; silicon carbide; laser doping; Optics
An n-type 4H-SiC substrate is doped with gallium using a laser doping technique and its optical response is investigated at the mid-wave infrared (MWIR) wavelength 4.21 mu m as a function of the dopant concentration. The dopant creates a p-type energy level of 0.3 eV, which is the energy of a photon corresponding to the MWIR wavelength 4.21 mu m. Therefore, Ga-doped SiC can be used as an uncooled MWIR detector because an optical signal was obtained at this wavelength when the sample was at room temperature. The energy level of the Ga dopant in the substrate was confirmed by optical absorption spectroscopy. Secondary ion mass spectroscopy ( SIMS) of the doped samples revealed an enhancement in the solid solubility of Ga in the substrate when doping is carried out by increasing the number of laser scans. A higher dopant concentration increases the number of holes in the dopant energy level, enabling photoexcitation of more electrons from the valence band by the incident MWIR photons. The detector performance improves as the dopant concentration increases from 1.15 x 10(19) to 6.25 x 10(20) cm(-3). The detectivity of the optical photodetector is found to be 1.07 x 10(10) cm Hz(1/2) W-1 for the case of doping with four laser passes.
Journal of Optics
"Improved optical properties and detectivity of an uncooled silicon carbide mid-wave infrared optical detector with increased dopant concentration" (2012). Faculty Bibliography 2010s. 2935.