@article{Lv2026, 
author = {Wentao Lv and Zhikang Ao and Baihui Zhang and Yang Du and Jianing Xie and Luyao Wang and Wenkui Wen and Yinghao Chen and Qinglin Xia and Zhengwei Zhang},
title = {Temperature-dependent polymorph evolution of NbSe2 on WSe2 via van der Waals epitaxy},
year = {2026},
journal = {Nano Research},
keywords = {polymorph engineering, van der Waals epitaxy, phase-selective growth, two-dimensional heterostructures, temperature-programmable synthesis, transition metal dichalcogenides},
url = {https://www.sciopen.com/article/10.26599/NR.2026.94909064},
doi = {10.26599/NR.2026.94909064},
abstract = {Polymorph engineering in two-dimensional transition metal dichalcogenides provides an effective route for tuning structure-dependent electronic properties, yet controllable phase-selective growth remains challenging because polymorph stability is highly sensitive to growth conditions. In particular, achieving reliable phase selectivity in chemical vapor deposition (CVD) without modifying precursor chemistry or introducing external perturbations remains difficult. Here, we report a temperature-dependent CVD growth strategy for phase-selective synthesis of NbSe2 on atomically flat WSe2 substrates. By tuning the growth temperature, rhombohedral 3R-NbSe2 and hexagonal 2H-NbSe2 can be selectively obtained within distinct temperature windows, with a coexistence region observed at intermediate conditions. Structural and spectroscopic characterizations reveal clear differences in morphology, stacking configuration, and vibrational properties between the two polymorphs, while atomic-resolution microscopy confirms the formation of atomically sharp and chemically abrupt interfaces. The observed temperature-dependent phase evolution suggests that surface diffusion and nucleation behavior may play important roles during growth. In addition, metallic NbSe2 exhibits improved carrier injection as a contact electrode, highlighting its potential for device integration. This work demonstrates a feasible approach for temperature-dependent phase-selective growth in CVD-grown two-dimensional heterostructures.}
}