A novel hybrid phototransistor consisting of molybdenum carbide (Mo2C) and molybdenum disulfide (MoS2) is proposed. By exploiting the interface properties of MoS2 and Mo2C, a highly sensitive and broad‐spectral response photodetector is fabricated. The underlying mechanism of the enhanced performance is the efficient hot carrier injection from Mo2C to MoS2. The strong coupling of MoS2 and Mo2C at the interface provides the significantly low Schottky barrier height (≈70 meV), which gives rise to the significantly efficient hot carrier transfer from Mo2C to MoS2. The grating of metallic Mo2C produces plasmonic resonance, which provides hot carriers to the MoS2 channel. By adjusting the grating period of Mo2C (400–1000 nm), the optimal photoresponse of light can be controlled, from visible to NIR. By integrating various Mo2C multigrating periods (400–1000 nm) with MoS2, a novel photodetector is demonstrated with high responsivity (R > 103 A W−1) and light‐to‐dark current ratio (>102) over a broad spectral range (405–1310 nm). The proposed novel hybrid photodetector, 2D semiconductors with multigrating 2D metallic stripes, exhibits high sensitivity and broad spectral detection of light and can overcome the inherent weakness of conventional 2D photodetectors, paving the way forward for next‐generation photoelectric devices.

Exploiting the layer-dependent semiconductor-to-semimetal transition property, a PtSe2 device with homogeneous coplanar structure demonstrate high mobility and extremely low contact resistance.

Abstract Two-dimensional (2D) layers of transition metal carbides, nitrides, or carbonitrides, collectively referred to as MXenes, are considered as the new family of 2D materials for the development of functional building blocks for optoelectronic and photonic device applications. Their advantages are based on their unique and tunable electronic and optical properties, which depend on the modulation of transition metal elements or surface functional groups. In this paper, we have presented a comprehensive review of MXenes to suggest an insightful perspective on future nanophotonic and optoelectronic device applications based on advanced synthesis processes and theoretically predicted or experimentally verified material properties. Recently developed optoelectronic and photonic devices, such as photodetectors, solar cells, fiber lasers, and light-emitting diodes are summarized in this review. Wide-spectrum photodetection with high photoresponsivity, high-yield solar cells, and effective saturable absorption were achieved by exploiting different MXenes. Further, the great potential of MXenes as an electrode material is predicted with a controllable work function in a wide range (1.6–8 eV) and high conductivity (~104 S/cm), and their potential as active channel material by generating a tunable energy bandgap is likewise shown. MXene can provide new functional building blocks for future generation nanophotonic device applications.

Recently, for overcoming the fundamental limits of conventional silicon technology, multivalued logic (MVL) circuits based on two-dimensional (2D) materials have received significant attention for reducing the power consumption and the complexity of integrated circuits. Compared with the conventional silicon complementary metal oxide semiconductor technology, new functional heterostructures comprising 2D materials can be readily implemented, owing to their unique inherent electrical properties. Furthermore, their process integration does not pose issues of lattice mismatch at junction interfaces. This facilitates the realization of new functional logic gate circuit configurations. However, the reported three-valued NOT gates (ternary inverters) based on 2D materials require stringent operating conditions and complex fabrication processes to obtain three distinct logic states. Herein, a general structure of MVL devices based on a simple series connection of 2D materials with partial surface functionalization is demonstrated. By arranging three 2D materials exhibiting p-type, ambipolar, and n-type conductivities, ternary inverter circuits can be established based on the complementary driving between 2D heterotransistors. This ternary inverter circuit can be further improved for quaternary inverter circuits by controlling the charge neutral point of partial ambipolar 2D materials using surface functionalization, which is an effective and nondestructive doping method for 2D materials.