Near Ultraviolet Photoresponse of a Silicon Carbide and Tantalum Boride Heterostructure

Silicon carbide (SiC) is widely used in abrasives, heating devices, light emitting diodes and high-power electronics, because of its unique physical-chemical properties including high hardness, high melting point, excellent thermal conductivity, and wide bandgap. In recent years, its color centers have also been used as potential sources of single photons. Given that borides and carbides are refractory materials, we decided to study a heterostructure formed by an n-doped silicon carbide substrate and a layer of tantalum monoboride (TaB) for near ultraviolet (UV) photodetection. It is shown that the addition of TaB creates a rectifying device that can handle currents higher than 300 mA, showing its potential for high-power optoelectronic devices. The detector also has a high responsivity of 2.9 A/W at the free-space wavelength of 405 nm and a fast frequency response of 610 kHz. The high performance of the detector is attributed to the high thermal and electrical conductivity, large bandgap of SiC, and its moderately close match in atomic arrangement with TaB. Such heterostructure offers a simple method to produce high-performance near UV photodetectors operating under hard conditions such as high power, high temperature and corrosive or oxidizing environments.