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This study presents the fabrication of highly photosensitive undoped zinc oxide (ZnO) thin films for vacuum ultraviolet (VUV) radiation detection, covering the wavelength range of 100–200 nm. ZnO films were deposited using hybrid pulsed reactive magnetron sputtering, assisted by ECWR (electron cyclotron wave resonance) plasma. Control of the ECWR power (PECWR), ranging from 0 to 380 W, played a crucial role in enhancing the films’ photoconductive properties. At PECWR = 200 W, the photosensitivity increased by 8 orders of magnitude compared to films deposited without ECWR assistance. This improvement was attributed to a sharp reduction in dark current due to lower defect density. Photoluminescence and cathodoluminescence spectra revealed a significant reduction in defect-related emissions for films deposited at PECWR = 200 W, confirming fewer intrinsic defects. Raman spectroscopy also showed a decrease in defect-related vibrational modes in the same films. Time-Resolved Microwave Conductivity (TRMC) measurements further supported these findings, demonstrating rapid recombination of charge carriers at 200 W, indicative of low trap densities. These results suggest that precise control of ECWR power allows for optimization of the defect concentration and crystallinity in ZnO films, paving the way for the development of high-sensitivity VUV photodetectors. [ABSTRACT FROM AUTHOR]

Ultrafast sub‐100 picosecond luminescence is vital in many applications involving ultrafast events and time‐of‐flight systems. Materials exhibiting fast luminescence, such as barium fluoride (BaF2) and zinc oxide (ZnO), also suffer from an intrinsically slow nanosecond (ns) to microsecond (µs) luminescence. Here, 2.2 micrometer (µm)‐ to 5.7 µm‐thick undoped ZnO films on soda‐lime glass (SLG) substrates without a buffer layer by a hybrid pulsed reactive magnetron sputtering operating in the medium‐frequency range (MF magnetron) assisted by an electron cyclotron wave resonance (ECWR) plasma is deposited. The undoped ZnO films exhibited superior optical properties characterized by intense ultraviolet (UV) luminescence, unprecedented ultrafast decay times, and for the case of MF+ECWR‐deposited films, suppressed defect‐related visible luminescence. The 2.2 µm‐thick MF‐deposited film exhibited the fastest 9‐ps decay time at room temperature. The impressive properties of the films are attributed to the use of advanced deposition technology with properly tuned plasma parameters, especially a high degree of dissociation of molecular oxygen together with an increased proportion of activated zinc particles, leading to a higher deposition rate, better crystallinity, fewer defects, and a lower proportion of oxygen vacancies. These films will pave the way toward the development of time‐of‐flight detectors, high‐resolution nuclear imaging cameras, and high‐rate ultrafast timing devices. [ABSTRACT FROM AUTHOR]

The incorporation of nitrogen into tetrahedral amorphous carbon films (ta-C:H) was investigated as a function of different gas sources, ion energies and substrate temperatures. Samples were deposited using a highly energetic plasma method: electron cyclotron wave resonance. Composition was measured by nuclear techniques or by XPS. The optical gap was determined by reflection and transmission measurements of samples deposited on quartz substrates and the bonding state was investigated by Raman and infrared (ir) spectroscopy. All the results suggest that tetrahedral bonding is lost, as the nitrogen content increases independently of the deposition parameters used. Structural changes indicated a more polymeric structure with the formation of >C=N, -C≡N and >NH groups. [ABSTRACT FROM AUTHOR]