Two‐Dimensional Miniature Spectrometer With High Reconstruction Accuracy and Small Footprint Based on Schottky Barrier Modulation

On‐chip computational spectrometers hold significant promise for developing integrated optoelectronic systems by eliminating the need for bulky dispersive components. 2D van der Waals (vdW) heterostructures provide a compelling platform for such miniaturized devices; however, the fabrication complexity and unavoidable interfacial defects severely hamper their application. There is a growing need for simplified device architectures with universal modulation strategies. Here, we demonstrate a miniature computational spectrometer based on a single 2D semiconductor phototransistor via vdW contact. This approach effectively suppresses Fermi‐level pinning, allowing dynamic modulation of Schottky barriers and distinct wavelength‐dependent anti‐ambipolar photoresponse. The device has a small footprint of ∼73 µm 2 and accurately reconstructs both monochromatic and broadband spectra across the visible range (380–680 nm), achieving an average reconstruction accuracy of ~0.75 nm and a spectral resolution below 10 nm. This universal architecture offers a promising pathway toward ultra‐compact hyperspectral imaging, spectroscopic sensing, and on‐chip optoelectronic integration.