The growth of GaAs nanowires directly on fused quartz substrates using molecular beam epitaxy via a vapor-liquid-solid mechanism with gold as catalyst is reported. Unlike conventional Au-catalyst MBE growth of nanowir...The growth of GaAs nanowires directly on fused quartz substrates using molecular beam epitaxy via a vapor-liquid-solid mechanism with gold as catalyst is reported. Unlike conventional Au-catalyst MBE growth of nanowires （NWs） on GaAs substrates, zinc blende is found to be the dominant crystal structure for NWs grown on fused-quartz substrates by MBE. Further transmission electron microscopy measurements show that the prepared ZB NWs have the growth direction of [112] and lamellar { 111 } twins extend through the length of NWs. Although there are longitudinal planar defects that extend through NWs, the narrow full width at half maximum of PL implies high crystal quality of NWs grown on fused-quartz substrates.展开更多
We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at ro...We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at room temperature.The zinc-blende to orthorhombic phase transition was observed at around 20.0 GPa.In the same pressure range, pressureinduced metallization of GaAs nanowires was confirmed by infrared reflectance spectra.The metallization originates from the zinc-blende to orthorhombic phase transition.Decompression results demonstrated that the phase transition from zincblende to orthorhombic and the pressure-induced metallization are reversible.Compared to bulk materials, GaAs nanowires show larger bulk modulus and enhanced transition pressure due to the size effects and high surface energy.展开更多
The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te...The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te energetically prefers to substitute the core Ga（Ef = 0.4111 eV） under As-rich conditions of Ga As nanowires, while on surface, the single Te tends to substitute the surface As site. With increasing the Te concentration, the favorable substitution sites are 2Te–Ga–A and 3Te–Ga–D. Thus, the stability of the structure of the electronic structure and optical properties are discussed.展开更多
基金Project supported by the National Natural Science Foundation of China(Nos.11104271,11179042)
文摘The growth of GaAs nanowires directly on fused quartz substrates using molecular beam epitaxy via a vapor-liquid-solid mechanism with gold as catalyst is reported. Unlike conventional Au-catalyst MBE growth of nanowires （NWs） on GaAs substrates, zinc blende is found to be the dominant crystal structure for NWs grown on fused-quartz substrates by MBE. Further transmission electron microscopy measurements show that the prepared ZB NWs have the growth direction of [112] and lamellar { 111 } twins extend through the length of NWs. Although there are longitudinal planar defects that extend through NWs, the narrow full width at half maximum of PL implies high crystal quality of NWs grown on fused-quartz substrates.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFA0305900)the National Natural Science Foundation of China(Grant No.11604116)+1 种基金Beijing Municipal Natural Science Foundation,China(Grant No.1192017)Youth Innovation Promotion Association,Chinese Academy of Sciences(Grant No.2017156)
文摘We investigate the structural phase transitions and electronic properties of GaAs nanowires under high pressure by using synchrotron x-ray diffraction and infrared reflectance spectroscopy methods up to 26.2 GPa at room temperature.The zinc-blende to orthorhombic phase transition was observed at around 20.0 GPa.In the same pressure range, pressureinduced metallization of GaAs nanowires was confirmed by infrared reflectance spectra.The metallization originates from the zinc-blende to orthorhombic phase transition.Decompression results demonstrated that the phase transition from zincblende to orthorhombic and the pressure-induced metallization are reversible.Compared to bulk materials, GaAs nanowires show larger bulk modulus and enhanced transition pressure due to the size effects and high surface energy.
基金supported by the Open Fund of State Key Laboratory of Information Photonics and Optical Communications(Beijing University of Posts and Telecommunications,China,No.2012LF1003)the Research Foundation of Education Bureau of Sichuan Province(No.16ZA0316)
文摘The first-principles calculations have been performed to determine the effects of Te doping to the structural, electronic, and optical properties of Ga As NWs. The calculated formation energies show that the single Te energetically prefers to substitute the core Ga（Ef = 0.4111 eV） under As-rich conditions of Ga As nanowires, while on surface, the single Te tends to substitute the surface As site. With increasing the Te concentration, the favorable substitution sites are 2Te–Ga–A and 3Te–Ga–D. Thus, the stability of the structure of the electronic structure and optical properties are discussed.
