Boron-doped diamond by 9 MeV microbeam implantation: Damage and recovery

Diamond properties can be tuned by doping and ion-beam irradiation is one of the most powerful techniques to do it in a controlled way, but it also produces damage and other aftereffects. Of particular interest is boron doping which, in moderate concentrations, causes diamond to become a p-type semiconductor and, at higher boron concentrations, a superconductor. Nevertheless, the preparation of superconducting boron-doped diamond by ion implantation is hampered by amorphization and subsequent graphitization after annealing. The aim of this work was to explore the possibility of creating boron-doped diamond superconducting regions and to provide a new perspective on the damage induced in diamond by MeV ion irradiation. Thus, a comprehensive analysis of the damage and eventual recovery of diamond when irradiated with 9 MeV B ions with different fluences has been carried out, combining Raman, photoluminescence, electrical resistivity, X-ray diffraction and Rutherford Backscattering/Ion-channeling. It is found that, as the B fluence increases, carbon migrates to interstitial sites outside of the implantation path and an amorphous fraction increases within the path. For low fluences (∼1015 ions/cm2), annealing at 1000 °C is capable to fully recovering the diamond structure without graphitization. However, for higher fluences (≥5 × 1016 ions/cm2), those required for superconductivity, the recovery is important, but some disorder still remains. For high fluences, annealing at 1200 °C is detrimental for the diamond lattice and graphite traces appear. The incomplete healing of the diamond lattice and the interstitial location of B can explain that optimally doped samples do not exhibit superconductivityThis work has been partially supported by the Ministerio de Ciencia e Innovacion ´ of Spain (Project grants PID2020-112770RB-C22/MCIN/ AEI/10.13039/501100011033, PID2021-127033OB-C21/MCIN/AEI/ 10.13039/501100011033, and PID2021-127498NB-I00/AEI/FEDER/ 10.13039/501100011033). We also acknowledge financial support from MCIN/AEI/10.13039/501100011033, through the “María de Maeztu” Programme for Units of Excellence in R&D (CEX2018-000805- M), as well as from the Autonomous Community of Madrid through program S2018/NMT-4321 (NANOMAGCOST-CM

Process design for the manufacturing of soft X-ray gratings in single-crystal diamond by high-energy heavy-ion irradiation

The dataset that supports the findings of this study are archived in the Universidad Autónoma de Madrid data repository e‐cienciaDatos in https://doi.org/10.21950/ARZSJ1This paper describes in detail a novel manufacturing process for optical gratings suitable for use in the UV and soft X-ray regimes in a single-crystal diamond substrate based on highly focused swift heavy-ion irradiation. This type of grating is extensively used in light source facilities such as synchrotrons or free electron lasers, with ever-increasing demands in terms of thermal loads, depending on beamline operational parameters and architecture. The process proposed in this paper may be a future alternative to current manufacturing techniques, providing the advantage of being applicable to single-crystal diamond substrates, with their unique properties in terms of heat conductivity and radiation hardness. The paper summarizes the physical principle used for the grating patterns produced by swift heavy-ion irradiation and provides full details for the manufacturing process for a specific grating configuration, inspired in one of the beamlines at the ALBA synchrotron light source, while stressing the most challenging points for a potential implementation. Preliminary proof-of-concept experimental results are presented, showing the practical implementation of the methodology proposed herei

Microwave plasma annealing of sol-gel deposited tantalum oxide and zinc oxide films

The sol-gel process allows the high throughput formation of transition metal oxide thin films. Microwave plasma annealing (MwPA) treatments have been performed on thin films of two different transition metal oxides, Ta2O5 and ZnO, selected as representatives of covalently and strongly ionic bonded oxides, respectively. Ta2O5 has been explored as a dielectric barrier for porous silicon structures. The main limitation of the sol-gel spin coating in this case is the surface roughness of the coating, which is highly improved upon Ar MwPA. The treatment leads additionally to a microstructural activation and interface development comparable to a 500ºC thermal annealing. The MwPA of ZnO is a quasi-equivalent process to a 200ºC thermal annealing, preventing grain growth and promoting nanocrystalline phases. This is suggested to have a direct impact on the optical and electronic properties of the ZnO films. The MwPA films show wider optical band gap than thermally annealed ones. An impedance analysis further shows that the MwPA ZnO films present lower equivalent resistance and higher equivalent capacitance than the thermal films. These results are promising for the development of new processing routes for widely demanded transition metal oxide thin filmsThis research was partially funded through grant MAT2014-54826- C2-1- R from Ministerio de Economía y Competitivida

Tools for investigating electronic excitation: experiment and multi-scale modelling

This book collects the lectures presented in the first COST TUMIEE Training School held in Greece in 2019, supplemented with specific applications that illustrate how the multi-scale approach is implemented in specific cases of interest. The book is intended both as a reference in the field and as a textbook for people becoming interested or entering the field. The first part focuses on experimental methods, the second on theoretical approaches, and the third on cases of interest