Synthesis of nanocrystalline δ-MoN by thermal annealing of amorphous thin films grown on (100) Si by reactive sputtering at room temperature

Abstract

We report on the synthesis and characterization of nanocrystalline δ-MoN by crystallization of amorphous thin films grown on (100) Si by reactive sputtering at room temperature.Films with chemical composition MoN were grown using a deposition pressure of 5mTorr with a reactive mixture of Ar/(Ar+N 2 )=0.5. The as-grown films display mostly amorphous structure. Nanocrystalline δ-MoN phase is obtained after annealing at temperatures above 600 °C. The superconducting critical temperature T c depends on film thickness. Thick films (170 nm) annealed at 700 °C for 30 min display a T c = 11.2 K (close to the one reported for bulk specimens: 13 K), which is gradually suppressed to 7.2 K for 40 nm thick δ-MoN films. Our results provide a simple method to synthesize superconducting nitride thin films on silicon wafers with T c above the ones observed for conventional superconductors such as Nb.

Effect of film thickness on the structural and tribo-mechanical properties of reactive sputtered molybdenum nitride thin films

“…However, due to the thinness of the film, no preferential orientations for the Mo-N phases were observed in the X-ray diffraction spectrum, as previously confirmed [19]. Additionally, subjected to molybdenum oxides, for which the maximum intensities are around 20 to 30°, the signal is also weak.…”

“…For example, N. Haberkorn et al made nanocrystalline MoN by crystallizing it with reactive DC sputtering at room temperature using a N2/(Ar+N2) = 0.5 mixture. They found that the annealed MoN film had an amorphous structure and a good superconducting critical temperature at about 170 nm thickness [19].…”

Effect of thermal annealing and irradiation damage on the superconducting critical temperature of nanocrystalline γ-Mo2N thin films

“…The small shift at the Mo + component ( 0.2-0.3 eV) observed for the pristine and irradiated films can be related to final state effects due to the presence of oxides that prevents the fast neutralization of the hole created during the photoemission process. No features related to the -MoN component are observed in the annealed film [21].…”

Recent Progress in the Nanoskiving Approach: A Review of Methodology, Devices, and Applications

“…One feasible common solution was to obtain polycrystalline thin films by high‐temperature annealing after film deposition, which required both high‐temperature resistant equipment and unattainable optimized parameters. [ 24,25 ] The chemical synthesis method offers an alternative “bottom–up” approach that can synthesize high‐quality products, including single‐crystal thin films [ 26–28 ] and single‐crystal nanowires. [ 29–31 ] For example, Watson et al.…”

“…One feasible common solution was to obtain polycrystalline thin films by hightemperature annealing after film deposition, which required both hightemperature resistant equipment and unattainable optimized parameters. [24,25] The chemical synthesis method offers an alternative "bottom-up" approach that can synthesize highquality products, including single crystal thin films [26][27][28] and singlecrystal nanowires. [29][30][31] For example, Watson et al reported a method for fabrication of functional quantum dots by nanoskiving GaAs/AlGaAs quantumdotinnanowire systems that were grown using the autocatalytic vaporliquidsolid (VLS) approach (Figure 4b).…”