Dogukan Hazar Ozbey

As the semiconductor industry faces growing demand for high-performance (HP) nanoscale devices, two-dimensional (2D) materials have emerged as promising candidates to challenge the long-standing dominance of silicon. Among them, 2D GaSe has recently attracted significant interest as a group-III monochalcogenide with a tunable electronic structure and strong mechanical robustness, offering unique opportunities for ultra-scaled device applications. In this work, we perform first-principles density functional theory combined with nonequilibrium Green’s function simulations to systematically investigate the electronic transport properties of GaSe nanodevices with channel lengths of approximately 5 nm across three complementary architectures: p–n junction diodes, p–i–n field-effect transistors (FETs), and double-gate (DG) metal-oxide-semiconductor FETs (MOSFETs). Our results reveal that GaSe p–n junctions exhibit a pronounced backward-diode response, where the reverse current exceeds the forward current due to efficient interband tunneling. Extending the architecture to p–i–n FETs demonstrates that electrostatic gating enables controllable modulation of this tunneling-dominated transport, where moderate gate voltages ( V g ) suppress reverse conduction, whereas stronger gating restores and enhances carrier flow. Furthermore, DG GaSe MOSFETs exhibit competitive performance metrics when benchmarked against the International Technology Roadmap for Semiconductors-2028 (ITRS-2028) HP targets. Specifically, the zigzag n-type configuration achieves an on/off current ratio ( I on / I off ), intrinsic delay time ( τ ), and power-delay product that meet or surpass the projected HP requirements for ultra-scaled logic transistors. Collectively, these findings establish the monolayer 2D GaSe as a versatile semiconductor platform capable of integrating backward-diode functionality, gate-tunable tunneling devices, and HP MOSFET operation within a unified material system. This multifunctional capability highlights the strong technological potential of GaSe for next-generation ultra-scaled nanoelectronic applications.

The continuous demand for high‐performance (HP), energy‐efficient transistors is driving research beyond conventional silicon‐based metal‐oxide‐semiconductor field‐effect transistors (MOSFETs), which face critical scaling limits. To address this challenge, new channel materials and device architectures are being explored. Here, we investigate sub‐5 nm double‐gate (DG) MOSFETs based on 2D SiAs using first‐principles calculations combined with the non‐equilibrium Green's function (NEGF) formalism. SiAs monolayers exhibit an indirect bandgap of 1.58 eV and favorable electronic characteristics for device applications. We evaluate key performance metrics, including the on/off current ratio (I _on /I _off ), subthreshold swing (SS), gate capacitance (C _g ), intrinsic delay time (τ), and power–delay product (PDP). Underlap ( UL ) architectures with 1–2 nm extensions enhance device performance, yielding on‐state currents (I _on ) up to 1206 µA µm ⁻¹ , in line with the International Technology Roadmap for Semiconductors (ITRS) 2028 HP requirements. The SS values (112–142 mV dec ⁻¹ ) together with minimized τ and PDP indicate the suitability of SiAs transistors for ultra‐scaled, energy‐efficient technologies. Our findings highlight 2D SiAs as a promising candidate to overcome the scaling challenges of traditional MOSFETs and to advance next‐generation semiconductor devices.

Two-dimensional (2D) silicon phosphide (SiP) has recently emerged as a promising semiconductor for electronic, optoelectronic, and thermoelectric applications due to its unique electronic and structural characteristics. One-dimensional (1D) nanoribbons (NRs) derived from 2D SiP offer a versatile and scalable platform for device miniaturization and performance enhancement in nanoelectronics. Motivated by their potential, we present a comprehensive first-principles investigation of the structural, electronic, dynamical, and electronic transport properties of SiP-NRs. Specifically, we focus on both bare and hydrogen-passivated armchair (A-NRs, HA-NRs) and zigzag (Z-NRs, HZ-NRs) configurations. Our results reveal that hydrogen passivation effectively suppresses edge reconstructions observed in bare SiP-NRs, thus dynamically stabilizing their structures. Analysis of electronic band structures demonstrates a clear width-dependent oscillatory behavior of the band gap in bare A-NRs, which diminishes significantly upon hydrogen termination. The width-scaled electronic conductance ( G e ws ) of HA-NRs exhibits a decreasing trend with increasing ribbon width, featuring distinct even-odd oscillations for n -type transport due to subband splitting effects. In contrast, HZ-NRs display notable deviations in p -type conductance from their 2D SiP counterpart, particularly at low temperatures (around 100 K), arising from residual localized edge states. However, with increasing width and temperature, transport behavior converges toward that of 2D SiP monolayers, indicating diminishing edge effects. Unlike their p -type counterparts, the n -type G e values of the largest HA-NRs and HZ-NRs increase with the square root of temperature, similar to the n -type conductance trend observed in 2D SiP. This behavior is attributed to the evolution of the electronic transmission function ( τ ( E ) ) from a steplike profile in narrow ribbons to an E 1 / 2 dependence in wider ribbons, analogous to the 2D counterpart. These findings highlight the significant influence of width and edge termination on the transport characteristics of SiP-NRs and underline their potential as fundamental building blocks for high-performance nanoelectronic and thermoelectric quasi-1D devices.

The semiconductor industry’s quest for miniaturization has driven the exploration of new materials and innovative designs. Among these, two-dimensional (2D) semiconductor materials have emerged as promising candidates due to their unique electrical conductivity and superior carrier transport properties, which address the limitations of conventional bulk semiconductors at the nanoscale. Understanding the electronic transport properties of 2D materials is essential for unlocking their full potential in emerging nanoelectronic applications. In this context, our study focuses on the transport characteristics of Janus Ge2PAs monolayer-based metal–semiconductor–metal (MSM) devices. Utilizing DFT (density functional theory) simulations coupled with the nonequilibrium Green’s function method, we explore the effects of external factors, such as channel length and electrode doping concentration on device performance in the ballistic region (sub-10 nm). By modeling two-probe MSM nanodevices, we analyze transmission coefficients [T(E)] under varying bias voltages and study the I–V characteristics’ dependence on channel lengths and doping concentrations. Our findings provide valuable insights into the electronic transport properties of the Janus Ge2PAs monolayer and offer guidance for the design and optimization of 2D material-based nanoelectronic devices.

In this study, we designed a platform based on a laser-driven approach for fast, efficient, and controllable MOF synthesis. The laser irradiation method was performed for the first time to synthesize Zn-based MOFs in record production time (approximately one hour) compared to all known MOF production methods with comparable morphology. In addition to well-known structural properties, we revealed that the obtained ZnMOFs have a novel optical response, including photoluminescence behavior in the visible range with nanosecond relaxation time, which is also supported by first-principles calculations. Additionally, photocatalytic degradation of methylene blue with ZnMOF was achieved, degrading the 10 ppm methylene blue (MB) solution 83% during 1 min of irradiation time. The application of laser technology can inspire the development of a novel and competent platform for a fast MOF fabrication process and extend the possible applications of MOFs to miniaturized optoelectronic and photonic devices.