Dual-Gate Phototransistor for Electrically Tunable Image Edge Detection

Sensor-rich platforms demand reduced redundant data transmission for efficient operation, and in-sensor computing offers an effective solution. However, constrained by material properties and structure, sensing and computing units are physically separated. This has motivated the exploration of novel materials and device architectures to meet the growing demand of applications. In this work, we present a tellurium-based dual-gate (DG) phototransistor that responds across a wide spectral range (450-1870 nm). The phototransistor achieves a responsivity (R) of 0.2 A/W and a specific detectivity (D*) of 1.12 × 109Jones at 1550 nm. To demonstrate an application, the co-modulation of the dual gates enables the phototransistor to perform in situ edge extraction, physically emulating the core function of a Sobel filter. This is achieved by utilizing the device's photocurrent, which is directly proportional to the spatial gradient of image edges, to extract horizontal and vertical edges. The resulting edge maps exhibit a Structural Similarity Index (SSIM) up to 0.955 and a Peak Signal-to-Noise Ratio (PSNR) up to 37 dB.