This paper presents a detailed study of the electronic transport and photoelectric properties of a WTe2 − MoTe2 heterostructure phototransistor, designed to enhance performance in ultraviolet and infrared photodetection applications. Using density functional theory and non-equilibrium Green’s function methods, we simulate the device’s behavior under diferent gate voltages and light polarizations to assess its efectiveness in spectral response and charge transport. The WTe2 − MoTe2 p-n junction demonstrates a favorable type-II band alignment, enabling efcient separation of photogenerated carriers. The results reveal that the device achieves a high rectifcation ratio of 105 , a photoresponsivity of 67.6 mA/W, an external quantum efciency of 31.12%, and a detectivity of 2.7 × 1010 Jones, positioning it as a strong competitor among similar phototransistors. The phototransistor shows peak photoresponsivity under Z-polarized light in the infrared and violet regions (1.05 eV and 3.2 eV) and exhibits heightened sensitivity in the ultraviolet range (4.6 eV) under Y-polarized light. The application of gate voltages further enhances ultraviolet detection, underscoring the tunable nature of the device’s photoelectric response. These results identify the WTe2 − MoTe2 heterostructure as a promising candidate for high-sensitivity, broadband photodetection, demonstrating its versatility across various spectral ranges for advanced optoelectronic systems requiring selective sensitivity and efcient light detection
