Composition Modulation-Mediated Band Alignment Engineering from Type I to Type III in 2D vdW Heterostructures
Dingli Guo a
a Southeast University, Nanjing, China
Proceedings of MATSUS Spring 2026 Conference (MATSUSSpring26)
D4 Synthesis and Integration of 2D Materials for Electronics, Photonics, and Functional Devices
Barcelona, Spain, 2026 March 23rd - 27th
Organizers: Nikolas Antonatos and Filipa M. Oliveira
Poster, Dingli Guo, 852
Publication date: 15th December 2025

Band alignment engineering is crucial for facilitating charge separation and transfer in optoelectronic devices, which ultimately dictates the behavior of Van der Waals heterostructures (vdWH)-based photodetectors and light emitting diode (LEDs). However, the impact of the band offset in vdWHs on important figures of merit in optoelectronic devices has not yet been systematically analyzed. Herein, the regulation of band alignment in WSe2/Bi2Te3-xSex vdWHs (0 ≤ x ≤ 3) is demonstrated through the implementation of chemical vapor deposition (CVD). A combination of experimental and theoretical results proved that the synthesized vdWHs can be gradually tuned from Type I (WSe2/Bi2Te3) to Type III (WSe2/Bi2Se3). As the band alignment changes from Type I to Type III, a remarkable responsivity of 58.12 A W−1 and detectivity of 2.91×1012 Jones (in Type I) decrease in the vdWHs-based photodetector, and the ultrafast photoresponse time is 3.2 μs (in Type III). Additionally, Type III vdWH-based LEDs exhibit the highest luminance and electroluminescence (EL) external quantum efficiencies (EQE) among p-n diodes based on Transition Metal Dichalcogenides (TMDs) at room temperature, which is attributed to band alignment-induced distinct interfacial charge injection. This work serves as a valuable reference for the application and expansion of fundamental band alignment principles in the design and fabrication of future optoelectronic devices.

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