GaAs nanowires are synthesized on fused quartz substrates by using molecular beam epitaxy via a vapor-liquidsolid mechanism with gold as the catalyst. High resolution-transmission electron microscopy is used to probe ...GaAs nanowires are synthesized on fused quartz substrates by using molecular beam epitaxy via a vapor-liquidsolid mechanism with gold as the catalyst. High resolution-transmission electron microscopy is used to probe crystal quality and growth direction. Miero-photolumineseenee measurements are carried out to examine the optical properties of GaAs NWs. The low-temperature photoluminescenee （PL） emission of nanowires （NWs） has a peak at 1.513eV, 2meV lower than the zinc blende GaAs free exciton energy. The temperature-dependent band gap of NWs is seen to be somewhat different from that observed in bulk OaAs, and the PL rapidly quenches above 150K, with an activation energy of 6.3meV reflecting the presence of the longitudinal twins＇ structure.展开更多
Copper doped n-type single-crystal silicon materials are prepared by a high temperature diffusion process. The electrical and thermal-sensitive characteristic of materials is investigated under different experimental ...Copper doped n-type single-crystal silicon materials are prepared by a high temperature diffusion process. The electrical and thermal-sensitive characteristic of materials is investigated under different experimental conditions. The results show that the maximum resistivity of 46.2 Ω·cm is obtained when the sample is treated at 1200℃ for 2 h with the surface concentration of the copper dopant source being 1.83×10^7mol/cm^2. The copper doped n-type silicon material presents a negative temperature-sensitive characteristic and the B values are about 3010–4130 K.展开更多
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
文摘GaAs nanowires are synthesized on fused quartz substrates by using molecular beam epitaxy via a vapor-liquidsolid mechanism with gold as the catalyst. High resolution-transmission electron microscopy is used to probe crystal quality and growth direction. Miero-photolumineseenee measurements are carried out to examine the optical properties of GaAs NWs. The low-temperature photoluminescenee （PL） emission of nanowires （NWs） has a peak at 1.513eV, 2meV lower than the zinc blende GaAs free exciton energy. The temperature-dependent band gap of NWs is seen to be somewhat different from that observed in bulk OaAs, and the PL rapidly quenches above 150K, with an activation energy of 6.3meV reflecting the presence of the longitudinal twins＇ structure.
基金Project supported by the National High Technology Research and Development Program of China(No.2012AA091102)the National Natural Science Foundation of Xinjiang(No.2010211B24)
文摘Copper doped n-type single-crystal silicon materials are prepared by a high temperature diffusion process. The electrical and thermal-sensitive characteristic of materials is investigated under different experimental conditions. The results show that the maximum resistivity of 46.2 Ω·cm is obtained when the sample is treated at 1200℃ for 2 h with the surface concentration of the copper dopant source being 1.83×10^7mol/cm^2. The copper doped n-type silicon material presents a negative temperature-sensitive characteristic and the B values are about 3010–4130 K.
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.
