Conference Agenda

We present a theoretical investigation of a previously

unexplored dilute nitride III-V-N short-period superlattice

system, GaPN/GaAsP, designed as a potential top-cell

absorber for monolithic III-V/Si tandem solar cells. This

system exhibits a type-II band alignment. Through

multiband k·p calculations and the envelope function

approximation, we show that an optimal bandgap of 1.7

eV can be achieved while satisfying the strain-balanced,

zero-stress condition over a broad range of dilute

nitrogen compositions. The thicknesses of individual

layers remain well below the critical threshold for plastic

relaxation. We also discuss the experimental feasibility of

realizing such structures, supported by recent progress in

the growth of high-quality GaP buffer layers and precise,

monolayer-controlled incorporation of nitrogen in dilute

nitrides on silicon via molecular beam epitaxy.

We present large-signal load-pull measurements of a transferred InP/GaAsSb double heterojunction bipolar transistor fabricated on a high-resistivity silicon substrate. The tested devices feature an emitter area of 0.44 × 3.9 µm². When biased for highest power, an output power of 13.42 dBm was achieved corresponding to a power density of 12.92 mW/µm² (5.68 W/mm). A peak value of 23.7% was obtained along with a power gain of 5.35 dB when the load impedance was optimized for maximum power-added efficiency (P.A.E). These results highlight the benefits of thermal dissipation improvement in overcoming self-heating effects to achieve high output power.

This study investigates the effects of Ni and O vacancies on the electronic and optoelectronic properties of NiO using density functional theory (DFT) alongside cathodoluminescence experiments. Computational results obtained with the B3LYP hybrid functional closely match experimental band gaps, validating the reliability of our simulations. Specifically, the introduction of Ni vacancies produces intra-gap states that align well with experimentally observed emission peaks. In contrast, O vacancies demonstrate donor-like behavior, aligning with experimental reports of enhanced n-type conductivity. These findings provide critical insights for defect engineering strategies, bridging theoretical predictions with experimental data to optimize NiO for advanced optoelectronic applications.

Control elements based on III-V semiconductors are widely used in radiofrequency circuits, especially in the GHz range, as they offer superior high-frequency performance, easy integration, high reliability and compact size. In this context, PIN diodes are one of the most popular choices for limiter and switch applications. However, there is little literature connecting their structure and physical configuration with their circuit response, which hinders further understanding of these devices. In this regard, we present an analysis of the performance of GaAs and AlGaAs/GaAs PIN diodes as possible switches/limiters in X-Band applications, where we have conducted simulations on their high frequency behaviour, employing the Silvaco ATLAS numerical simulation software. Variations in the physical structure of the PIN diodes have been explored, and the resulting changes in their high frequency response have been evaluated. In this communication, we present a sample of the most relevant metrics explored for X-band operation (8-12 GHz), such as as R-I characteristics under forward bias, insertion losses and band structures for all PIN designs.

Single-photon emitters (SPEs) in wide-bandgap materials, like group III-nitrides, are promising for room-temperature single-photon sources. Recent studies have shown antibunched emission from colour centres in gallium nitride and aluminum nitride (AlN). However, the nature of these defects and optimal formation conditions are still unclear.

In this work, we investigated the effect of aluminum implantation on AlN epilayers, followed by thermal annealing and confocal microscopy. The results showed that the SPEs density increased with fluence, with ensembles forming at the highest implantation fluence and that the use of thermal annealing at 600°C increases the number of individual colour centres for the highest fluences. A second study tracked native and created SPEs in a patterned sample, revealing that both native and fabricated ones were present near the sapphire interface. These findings highlight the importance of vacancy formation for SPEs creation and offer new possibilities for defect engineering in solid-state SPEs.

Deterministic single-ion implantation has become a critical focus in the semiconductor field, particularly for its applications in solid-state quantum technologies. The ability to precisely position single dopants in nanostructures is essential for developing quantum devices, driving significant advancements in implantation techniques. Among these, single-ion lithographic methods utilizing scanning probes achieve exceptional nanometer-scale accuracy but are limited by slow processing speeds. Direct ion implantation, by contrast, offers a more rapid and scalable solution, though at the cost of reduced spatial precision and constraints imposed by device architecture.

In this study, a novel approach utilizing an ultra-thin 4H-SiC membrane sensor for single-ion detection is presented. The membrane design enables ion detection by monitoring the energy deposited by the ions as they pass through the active layer of the sensor. With this experimental setup, a 96.5% ion counting confidence was achieved, underlining the potential of SiC membranes as high-fidelity in-beam ion sensors. However, the introduction of the SiC membrane impacts the ion beam trajectory, resulting in ion straggling and increased uncertainty in the dopant’s final position within the target. Using a scanning knife-edge technique and SRIM simulations, we quantified the ion straggling, observing an increase in the beam size from 3.43 µm to 8.15 µm. These findings highlight the trade-off between detection accuracy and spatial resolution, emphasizing the need for further optimization to minimize beam perturbations while maintaining high detection efficiency.