Exploring the Transverse Thermoelectric Effect of 4H-SiC Single Crystal for the Applications of High-Energy Infrared Laser Detection

Although the transverse thermoelectric (TTE) effect has been proposed for infrared (IR) laser detection, the development of cost-effective TTE materials for high-energy IR detection remains challenging. This work proposes a groundbreaking TTE material based on c-axis 4° tilted n-type 4H-SiC single crystals for IR laser detector applications. Pulsed lasers with wavelengths of 1080 nm and durations ranging from 5 to 40 ms were used as the irradiation sources. The voltages recorded on the 4H-SiC surface were demonstrated to originate from the TTE effect, driven by Seebeck coefficient anisotropy, as made evident by comparing signals from various electrode pairs. Additionally, the influence of the laser incidence angle on the peak voltage and decay time was investigated, which may enhance the theoretical understanding of the TTE effect. Furthermore, the response of the detectors at elevated temperatures, from room temperature (RT) to 400 °C, was evaluated. These results suggest that 4H-SiC single crystals are promising low-cost TTE materials for high-energy IR detection.