The integration of large-scale two-dimensional (2D) materials onto semiconductor wafers is highly desirable for advanced electronic devices, but challenges such as transfer-related crack, contamination, wrinkle and doping remain. Here, we developed a generic method by gradient surface energy modulation, leading to a reliable adhesion and release of graphene onto target wafers. The as-obtained wafer-scale graphene exhibited a damage-free, clean, and ultra-flat surface with negligible doping, resulting in uniform sheet resistance with only ~6% deviation. The as-transferred graphene on SiO₂/Si exhibited high carrier mobility reaching up ~10,000 cm² V⁻¹ s⁻¹, with quantum Hall effect (QHE) observed at room temperature. Fractional quantum Hall effect (FQHE) appeared at 1.7 K after encapsulation by h-BN, yielding ultra-high mobility of ~280,000 cm² V⁻¹ s⁻¹. Integrated wafer-scale graphene thermal emitters exhibited significant broadband emission in near-infrared (NIR) spectrum. Overall, the proposed methodology is promising for future integration of wafer-scale 2D materials in advanced electronics and optoelectronics.

Two-dimensional (2D) materials have got extensive attention for multifunctional device applications in advanced nanoelectronics and optoelectronics, such as field-effect transistors, photodiodes, and solar cells. In our work, we fabricated MoTe₂–MoS₂ van der Waals heterostructure photodetectors with great performance using the mechanical exfoliation method and restack technique. It is demonstrated that our MoTe₂–MoS₂ heterostructure photodetector device can operate without bias voltage, possessing a low dark current (10 pA) and high photocurrent on/off ratio (>10⁴). Importantly, the room temperature photoresponsivity of the MoTe₂–MoS₂ photodetector can reach 110.6 and 9.2 mA W^–1 under λ = 532 and 1064 nm incident laser powers, respectively. Our results indicate that the van der Waals heterostructure based on 2D semiconducting materials is expected to play an important role in nanoscale optoelectronic applications.

A crystal structure has a profound influence on the physical properties of the corresponding material. By synthesizing crystals with particular symmetries, one can strongly tune their properties, even for the same chemical configuration (compare graphite and diamond, for instance). Even more interesting opportunities arise when the structural phases of crystals can be changed dynamically through external stimulations. Such abilities, though rare, lead to a number of exciting phenomena, such as phase-change memory effects. In the case of trilayer graphene, there are two common stacking configurations (ABA and ABC) that have distinct electronic band structures and exhibit very different behaviors. Domain walls exist in the trilayer graphene with both stacking orders, showing fascinating new physics such as the quantum valley Hall effect. Extensive efforts have been dedicated to the phase engineering of trilayer graphene. However, the manipulation of domain walls to achieve precise control of local structures and properties remains a considerable challenge. Here, we experimentally demonstrate that we can switch from one structural phase to another by laser irradiation, creating domains of different shapes in trilayer graphene. The ability to control the position and orientation of the domain walls leads to fine control of the local structural phases and properties of graphene, offering a simple but effective approach to create artificial two-dimensional materials with designed atomic structures and electronic and optical properties.