A new NPN structure detector based on SiC with internal gain characteristics was designed successfully.

This study aims to analyze the effect of area on the NPN detectors.

This research involves the design and fabrication of three dual-end SiC-based NPN structure radiation detectors with different areas. Their DC X-ray response characteristics were experimentally evaluated.

The results demonstrate that these detectors operate under the combined effects of externally biased voltage and photovoltaic voltage, exhibiting four distinct knee-points that divide the I-V characteristic curve into five stages. Under identical DC X-ray irradiation conditions, larger-area detectors absorb more X-ray energy, leading to stronger output signals. Smaller-area detectors show higher knee-points on the I-V characteristic curve, indicating a greater ability to withstand voltage. Additionally, the response time of the detectors is closely related to their size, with larger areas resulting in longer switch-off times. The 90%-10% fall time of the 1 cm×1 cm detector is approximately 12.2 ms longer than that of the 0.25 cm×0.25 cm detector.

These findings emphasize the importance of considering area in the design of radiation detectors and highlight the need to optimize this parameter to enhance the detector performance.