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2D Materials

In the realm of materials science, the discovery of graphene heralded a new era of exploration into two-dimensional materials (2DM). Since then, a plethora of novel 2D materials have emerged, each with unique properties and promising applications. Among these, transition metal dichalcogenides (TMDCs), MXenes, hexagonal boron nitride (h-BN), and hexagonal aluminum nitride (h-AlN) have garnered significant attention for their diverse range of properties and potential applications. In this article we delve into the properties and explore the exciting applications of these remarkable materials. 

2D Materials (2DM)

MXenes

MXenes are a family of 2D transition metal carbides, nitrides and carbonitrides, first synthesised in 2011. Unlike many other 2D materials, MXenes are derived from their bulk counterparts through selective etching of the ‘A’ layer, typically aluminum or silicon, from MAX phases. MXenes exhibit a unique combination of metallic conductivity and hydrophilicity, making them attractive for a wide range of applications.

The versatile properties of MXenes render them suitable
for energy storage, catalysis, sensing and electromagnetic interference shielding. They have been extensively studied for their use in supercapacitors and batteries due to their high specific capacitance and excellent rate capability. MXenes also show promise in catalytic applications, where their high surface area and metallic conductivity enhance reaction kinetics.

Hexagonal Boron Nitride (h-BN)

Hexagonal boron nitride (h-BN), also known as white graphene, shares a similar hexagonal lattice structure with graphene but consists of alternating boron and nitrogen atoms. Unlike graphene, h-BN is an insulator with a wide bandgap, making it an excellent dielectric material. Its exceptional thermal and chemical stability, combined with high thermal conductivity, make it an ideal candidate for high-temperature applications and thermal management.

h-BN finds applications in a variety of fields, including electronics, photonics and aerospace. It is utilised as a dielectric material in field-effect transistors (FETs), where its high breakdown voltage and low leakage current improve device performance. Additionally, h-BN serves as a substrate for graphene and other 2D materials, providing a stable and atomically flat surface for growth and device integration.

Hexagonal Aluminum Nitride (h-AlN)

Hexagonal aluminum nitride (h-AlN) is a wide-bandgap semiconductor with properties similar to those of h-BN. It exhibits excellent thermal conductivity, high electrical resistivity and chemical inertness, making it suitable for various electronic and optoelectronic applications. h-AlN is often employed as a substrate material for gallium nitride (GaN) devices due to its lattice matching and thermal expansion coefficient compatibility with GaN.

h-AlN has found applications in high-power electronics, UV optoelectronics and surface acoustic wave (SAW) devices. Its wide bandgap allows for the fabrication of UV photodetectors and light-emitting diodes (LEDs) with superior performance and efficiency. Moreover, h-AlN’s piezoelectric properties make it suitable for SAW devices used in wireless communication systems and sensors.

The exploration of 2D materials has unlocked a treasure trove of unique properties and promising applications. TMDCs, MXenes, h-BN and h-AlN exemplify the diverse range of materials available in the realm of 2D materials. Their unique properties are being explored in various high-impact applications. In electronics, these materials could be used in the next generation of transistors, memory devices and flexible electronics, offering potential solutions to the limitations of silicon-based technologies. Their optical and electronic properties are also exploited in the development of novel optoelectronic devices, including LEDs, lasers and photovoltaic cells.

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