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Two dimensional (2D) materials have generated enormous interest in various research fields in recent years due to their fascinating properties, such as atomic thickness, distinct structures and superior characteristics. In particular, electronic and optoelectronic devices based on 2D materials have been widely investigated, which is promising for the innovation of future nanoelectronics technology. Recently, the technique of laser processing 2D materials with the advantages of facile operation, versatility and low cost has been reported to enable the fabrication of diverse 2D material electronic and optoelectronic devices, such as field-effect transistors (FETs), p–n junction diodes, bipolar junction transistors (BJTs), inverters, memory devices, photodetectors, photovoltaic devices and light-emitting devices. Here, various interactions between lasers and 2D materials are introduced, such as direct writing processing, reduction, doping, phase transition engineering, thinning, oxidation and creating defects. The current advances in laser processing-assisted 2D material electronic and optoelectronic devices are reviewed. A comprehensive outlook on the future development of 2D material nanoelectronics/optoelectronics via laser processing is also presented.

Two-dimensional (2D) bipolar junction transistors (BJTs) with van der Waals heterostructures play an important role in the development of future nanoelectronics. Herein, a convenient method is introduced for fabricating a symmetric bipolar junction transistor (SBJT), constructed from black phosphorus and MoS2, with femtosecond laser processing. This SBJT exhibits good bidirectional current amplification owing to its symmetric structure. We placed a top gate on one side of the SBJT to change the difference in the major carrier concentration between the emitter and collector in order to further investigate the effects of electrostatic doping on the device performance. The SBJT can also act as a gate-tunable phototransistor with good photodetectivity and photocurrent gain of β = ∼21. Scanning photocurrent images were used to determine the mechanism governing photocurrent amplification in the phototransistor. These results promote the development of the applications of multifunctional nanoelectronics based on 2D materials.

Highly stable nanopores with precise size and film thickness are essential for ultrasensitive molecular biosensors and efficient ion filters. However, the stability of both solid-state nanopores and biological nanopores is of a few hours. Even for two-dimensional (2D) materials with excellent properties, it is very difficult to prepare nanopores with stability for more than 1 day. Here, in mechanically exfoliated 2D materials with excellent quality, highly stable nanopores have been fabricated. Through the manual control of defect density and laser spot irradiation, the breakdown process is more controllable. The nanopore diameter can be precisely adjusted from 1 to 10 nm. The 2 nm thick graphene nanopore (with a diameter of 2 nm) maintains good consistency in conductivity during the 1-month immersion in KCl (1 M) solution. The pore size changes less than 0.7% per day. We found that 2D material nanopores can produce a strong rectification ratio (∼50) due to the morphology undulation. In addition, our devices can recognize modified 5 nm Au nanoparticles, showing great potential for single-molecule detection. This work can guide the development of high-quality ion rectifier devices and biosensors based on 2D material nanopores.

The remarkable in-plane anisotropy of anisotropic two-dimensional materials (ATDMs), such as black phosphorus (BP), ReS2, and ReSe2, provides a new degree of freedom for the design of novel orientation-based optical and electronic devices. Therefore, visualization of the anisotropy and determination of the crystal orientation (CO) of ATDMs is of fundamental importance. Herein, using a setup equipped with a non-polarized beam splitter, a four-dimensional anisotropic imaging technique (AIT) based on the anisotropic optical response of ATDMs was proposed, by which the COs of many different ATDMs on the same substrate could be efficiently (

Achieving multifunctional van der Waals nanoelectronic devices on one structure is essential for the integration of 2D materials; however, it involves complex architectural designs and manufacturing processes. Herein, a facile, fast, and versatile laser direct write micro/nanoprocessing to fabricate diode, NPN (PNP) bipolar junction transistor (BJT) simultaneously based on a pre-fabricated black phosphorus/molybdenum disulfide heterostructure is demonstrated. The PN junctions exhibit good diode rectification behavior. Due to different carrier concentrations of BP and MoS2 , the NPN BJT, with a narrower base width, renders better performance than the PNP BJT. Furthermore, the current gain can be modulated efficiently through laser writing tunable base width WB , which is consistent with the theoretical results. The maximum gain for NPN and PNP is found to be ≈41 (@WB ≈600 nm) and ≈12 (@WB ≈600 nm), respectively. In addition, this laser write processing technique also can be utilized to realize multifunctional WSe2 /MoS2 heterostructure device. The current work demonstrates a novel, cost-effective, and universal method to fabricate multifunctional nanoelectronic devices. The proposed approach exhibits promise for large-scale integrated circuits based on 2D heterostructures.

van der Waals p-n heterostructures based on p-type black phosphorus (BP) integrated with other two-dimensional (2D) layered materials have shown potential applications in electronic and optoelectronic devices, including logic rectifiers and polarization-sensitive photodetectors. However, the engineering of carriers transport anisotropy, which is related to the linear dichroism, have not yet been investigated. Here, we demonstrate a novel van der Waals device of orientation-perpendicular BP homojunction based on the anisotropic band structures between the armchair and zigzag directions. The structure exhibits good gate-tunable diode-like rectification characteristics caused by the barrier between the two perpendicular crystal orientations. Moreover, we demonstrate that the unique mechanisms of the polarization-sensitivity properties of this junction are involved with the linear dichroism and the anisotropic carriers transport engineering. These results were verified by the scanning photocurrent images experiments. This work paves the way for 2D anisotropic layered materials for next-generation electronic and optoelectronic devices.

Reduced graphene oxide (RGO) has prospective applications in many fields, including energy storage, printable electronics, and sensing. RGO can simply be obtained at low-cost by reducing graphene oxide (GO). However, how to entirely remove the oxygen-containing groups to yield high-quality graphene is still a great challenge. Here, we report that high-quality intrinsic graphene can be prepared by a simple triggered microwave reduction method under air conditions. The induced spectrum and diffusion processes of GO reduction indicated that high-quality graphene could be produced by strong arc discharge caused by aggregation of electrons at the junction between graphene and GO under microwave irradiation. During the reduction process, the oxygen atoms were removed and carbon atoms were rearranged simultaneously in the graphene lattice structures. In addition, other triggered sources, such as iron wires and paper clips, could also be used to prepare high-quality graphene using the same method. Overall, the triggered microwave reduction of GO provides a simple and low-cost route for large-scale production of high-quality graphene.

Two-dimensional (2D) bipolar junction transistors (BJTs) with van der Waals heterostructures play an important role in the development of future nanoelectronics. Herein, a convenient method is introduced for fabricating a symmetric bipolar junction transistor (SBJT), constructed from black phosphorus and MoS

Vertically stacked devices of two-dimensional layered materials (2DLMs) based on van der Waals heterostructures (vdWHs) have recently attracted considerable attention due to their good properties. A tunneling structure is presented in this paper that, unlike other tunneling structures, has no specific insulating two-dimensional materials, such as boron nitride. The tunneling structure is comprised of graphene and black phosphorus. Black phosphorus is chemically active, and can be easily oxidized in the air to form an insulating layer. A tunneling device was produced based on this characteristic of black phosphorus. The insulation layer was an oxide layer formed by the oxidation of black phosphorus. The structure takes advantage of the easy oxidation ability of black phosphorus. The presence of a black phosphorus oxide layer was determined by XPS analysis. The tunneling characteristics of the overlay structure were determined by measuring the current-voltage (Id-V) curve of the device. Simulation studies showed that the oxidation layer was responsible for the tunneling effect. Compared with other black phosphorus devices, the photoelectric properties of the proposed device were greatly improved.

Despite many decades of research of diodes, which are fundamental components of electronic and photoelectronic devices with p-n or Schottky junctions using bulk or 2D materials, stereotyped architectures and complex technological processing (doping and multiple material operations) have limited future development. Here, a novel rectification device, an orientation-induced diode, assembled using only few-layered black phosphorus (BP) is investigated. The key to its realization is to utilize the remarkable anisotropy of BP in low dimensions and change the charge-transport conditions abruptly along the different crystal orientations. Rectification ratios of 6.8, 22, and 115 can be achieved in cruciform BP, cross-stacked BP junctions, and BP junctions stacked with vertical orientations, respectively. The underlying physical processes and mechanisms can be explained using "orientation barrier" band theory. The theoretical results are experimentally confirmed using localized scanning photocurrent imaging. These orientation-induced optoelectronic devices open possibilities for 2D anisotropic materials with a new degree of freedom to improve modulation in diodes.