The present article evaluates, in qualitative and quantitative manners, the characteristics (i.e., thickness of layers, crystal structures, growth orientation, elemental diffusion depths, edge, and screw dislocation densities), within two GaN/AlN/Si heterostructures, that alter their efficiencies as positron moderators. The structure of the GaN film, AlN buffer layer, substrate, and their growth relationships were determined through high-resolution transmission electron microscopy (HR-TEM). Data resulting from high-resolution X-ray diffraction (HR-XRD) was mathematically modeled to extract dislocation densities and correlation lengths in the GaN film. Positron depth profiling was evaluated through an experimental Doppler broadening spectroscopy (DBS) study, in order to quantify the effective positron diffusion length. The differences in values for both edge $({\rho }_{\mathrm{d}}^{\mathrm{e}})$ and screw $\left({\rho }_{\mathrm{d}}^{\mathrm{s}}\right)$ dislocation densities, and correlation lengths (L^e, L^s) found in the 690 nm GaN film, were associated with the better effective positron diffusion length (L_eff) of $L_{\mathrm{eff}}^{\mathrm{GaN}2}$ = 43 ± 6 nm.

This study assesses the characteristics (edge and screw dislocation density) of a commercially available GaN/AlN/Al₂O₃ wafer. The heterostructure was evaluated by means of high-resolution X-ray diffraction (HR-XRD), high-resolution transmission electron microscopy (HR-TEM), and Doppler-Broadening Spectroscopy (DBS). The results were mathematically modeled to extract defect densities and defect correlation lengths in the GaN film. The structure of the GaN film, AlN buffer, Al₂O₃ substrate and their growth relationships were determined through HR-TEM. DBS studies were used to determine the effective positron diffusion length of the GaN film. Within the epitaxial layers, defined by a [GaN $P63mc$ (0 0 0 2) || $P63mc$ AlN (0 0 0 2) || (0 0 0 2) $R\overline{3}c$ Al₂O₃] relationship, regarding the GaN film, a strong correlation between defect densities, defect correlation lengths, and positron diffusion length was assessed. The defect densities ${\rho }_{\mathrm{d}}^{\mathrm{e}}=$ 6.13 × 10¹⁰ cm⁻², ${\rho }_{\mathrm{d}}^{\mathrm{s}}=$ 1.36 × 10¹⁰ cm⁻², along with the defect correlation lengths L^e = 155 nm and L^s = 229 nm found in the 289 nm layer of GaN, account for the effective positron diffusion length L_eff~60 nm.

The use of Fe films as multi-element targets in space radiation experiments with high-intensity ultrashort laser pulses requires a surface structure that can enhance the laser energy absorption on target, as well as a low concentration and uniform distribution of light element contaminants within the films. In this paper, (110) preferred orientation nanocrystalline Fe thin films with controlled morphology and composition were grown on (100)-oriented Si substrates by oblique angle RF magnetron sputtering, at room temperature. The evolution of films key-parameters, crucial for space-like radiation experiments with organic material, such as nanostructure, morphology, topography, and elemental composition with varying RF source power, deposition pressure, and target to substrate distance is thoroughly discussed. A selection of complementary techniques was used in order to better understand this interdependence, namely X-ray Diffraction, Atomic Force Microscopy, Scanning and Transmission Electron Microscopy, Energy Dispersive X-ray Spectroscopy and Non-Rutherford Backscattering Spectroscopy. The films featured a nanocrystalline, tilted nanocolumn structure, with crystallite size in the (110)-growth direction in the 15–25 nm range, average island size in the 20–50 nm range, and the degree of polycrystallinity determined mainly by the shortest target-to-substrate distance (10 cm) and highest deposition pressure (10⁻² mbar Ar). Oxygen concentration (as impurity) into the bulk of the films as low as 1 at. %, with uniform depth distribution, was achieved for the lowest deposition pressures of (1–3) × 10⁻³ mbar Ar, combined with highest used values for the RF source power of 125–150 W. The results show that the growth process of the Fe thin film is strongly dependent mainly on the deposition pressure, with the film morphology influenced by nucleation and growth kinetics. Due to better control of film topography and uniform distribution of oxygen, such films can be successfully used as free-standing targets for high repetition rate experiments with high power lasers to produce Fe ion beams with a broad energy spectrum.

Several aspects such as the growth relation between the layers of the GaN/AlN/SiC heterostructure, the consistency of the interfaces, and elemental diffusion are achieved by High Resolution Transmission Electron Microscopy (HR-TEM). In addition, the dislocation densities together with the defect correlation lengths are investigated via High-Resolution X-ray Diffraction (HR-XRD) and the characteristic positron diffusion length is achieved by Doppler Broadening Spectroscopy (DBS). Moreover, a comparative analysis with our previous work (i.e., GaN/AlN/Si and GaN/AlN/Al₂O₃) has been carried out. Within the epitaxial GaN layer defined by the relationship $F\overline{4}3m$ (111) 3C-SiC || $P63mc$ (0002) AlN || $P63mc$ (0002) GaN, the total dislocation density has been assessed as being 1.47 × 10¹⁰ cm⁻². Compared with previously investigated heterostructures (on Si and Al₂O₃ substrates), the obtained dislocation correlation lengths (L^e = 171 nm and L^s =288 nm) and the mean distance between two dislocations (r_d = 82 nm) are higher. This reveals an improved crystal quality of the GaN with SiC as a growth template. In addition, the DBS measurements upheld the aforementioned results with a higher effective positron diffusion length $L_{\mathrm{eff}}^{\mathrm{GaN}2}$ = 75 ± 20 nm for the GaN layer.

Prostate cancer, a malignancy of significant prevalence, affects approximately half a million men in Europe, with one in twelve males receiving a diagnosis before reaching the age of 75. Radiotheranostics represents a paradigm shift in prostate cancer treatment, leveraging radionuclides for diagnostic and therapeutic applications, with PSMA emerging as the primary molecular target. Regulatory bodies have approved various PSMA-targeted radiodiagnostic agents, such as [¹⁸F]DCFPyL (PYLARIFY^®, Lantheus Holdings), [¹⁸F]rhPSMA-7.3 (POSLUMA^®, Blue Earth Diagnostics), and [⁶⁸Ga]Ga-PSMA-11 (LOCAMETZ^®, Novartis/ILLUCCIX^®, Telix Pharmaceuticals), as well as therapeutic agents like [¹⁷⁷Lu]Lu-PSMA-617 (PLUVICTO^®, 15 Novartis). The approval of PLUVICTO^® in March 2022 for patients with metastatic castration-resistant prostate cancer who have undergone prior treatments, including androgen receptor pathway-targeting agents and taxane-based chemotherapy, represents a significant advancement. Other radionuclides like ¹⁶¹Tb, ¹⁴⁹Tb, ²²⁵Ac, ²²⁷Th, ²²³Ra, ²¹¹At, ²¹³ Bi, ²¹²Pb, ⁸⁹Zr, and ¹²⁵I are presented, emphasizing their clinical implementation or the stage of clinical trial they are in in the flow to biomedical implementation. Three clinically wise used radionuclides ¹⁷⁷Lu, ²²⁵Ac, ²²³Ra are shown along with their characteristics. This review aims to elucidate the molecular mechanisms underpinning PSMA, explore the clinical applications of PSMA-targeted radiotheranostics, and critically examine the diverse challenges these therapies encounter in the treatment of prostate cancer.

Aluminum nitride (AlN) thin films were deposited on SiO₂ substrates by RF-magnetron sputtering at varying powers (110–140 W) and subsequently subjected to thermal annealing at 450 °C under nitrogen atmosphere. A comprehensive multi-technique investigation—including X-ray reflectometry (XRR), X-ray diffraction (XRD), scanning electron microscopy (SEM), atomic force microscopy (AFM), optical profilometry, spectroscopic ellipsometry (SE), and electrical measurements—was performed to explore the physical structure, morphology, and optical and electrical properties of the films. The analysis of the film structure by XRR revealed that increasing sputtering power resulted in thicker, denser AlN layers, while thermal treatment promoted densification by reducing density gradients but also induced surface roughening and the formation of island-like morphologies. Optical studies confirmed excellent transparency (>80% transmittance in the near-infrared region) and demonstrated the tunability of the refractive index with sputtering power, critical for optoelectronic applications. The electrical characterization of Au/AlN/Al sandwich structures revealed a transition from Ohmic to trap-controlled space charge limited current (SCLC) behavior under forward bias—a transport mechanism frequently present in a material with very low mobility, such as AlN—while Schottky conduction dominated under reverse bias. The systematic correlation between deposition parameters, thermal treatment, and the resulting physical properties offers valuable pathways to engineer AlN thin films for next-generation optoelectronic and high-frequency device applications.