In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a di...In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.展开更多
Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic dev...Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.展开更多
基金supported by the ERDF (European Regional Development Fund) through the COMPETE Programme (operational programme for competitiveness)by the Portuguese National Strategic Reference Framework (NSRF) through the project CFC-5568
文摘In this work, gallium phosphide thin films were deposited on glass substrates by radio frequency （RF） magnetron sputtering technique under different depositions conditions. The X-ray diffraction analysis showed a diversity of states： from amorphous in the films deposited at 175 ~C to a nearly stoichiometric and polycrystalline films, exhibiting cubic phase with preferred orientation along （220）, in the films deposited at temperatures higher than 250 ~C. Scanning electron microscopy images revealed that all films were uniform with a smooth surface, while the energy-dispersive spectroscopy （EDS） analysis showed that there was a visible dependence on the Ga/P ratio in the deposition conditions and confirmed that a residual Ga metallic phase was presented in the surface of all the films. The Raman analysis showed the structural evolution of the GaP films was strongly dependent on the deposition conditions. The conductivity of the films was slightly dependent on the argon pressure and the rf power, but strongly dependent on the deposition temperature, mainly above 200 ~C. The optical transmission and absorption analyses of the GaP films revealed an indirect band gap of ~ 1.70 eV in the films deposited at temperatures less than 200 ~C, which transited to a band gap of 2.26 eV as the deposition temperature was close to 300 ~C.
文摘Top-down lithography techniques allow the fabrication of nanostructured elements with novel spin configurations, which provide a new route to engineer and manipulate the magnetic response of sensors and electronic devices and understand the role of fundamental interactions in materials science. In this study, shallow nanostructure-patterned thin films were designed to present inverse magnetization curves, i.e., an anomalous magnetic mechanism characterized by a negative coercivity and negative remanence. This procedure involved a method for manipulating the spin configuration that yielded a negative coercivity after the patterning of a single material layer. Patterned NiFe thin films with trench depths between 15%-25% of the total film thickness exhibited inverse hysteresis loops for a wide angular range of the applied field and the trench axis. A model based on two exchange-coupled subsystems accounts for the experimental results and thus predicts the conditions for the appearance of this magnetic behavior. The findings of the study not only advance our understanding of patterning effects and confined magnetic systems but also enable the local design and control of the magnetic response of thin materials with potential use in sensor engineering.
