Electric field-induced point electron source is highly demanded for microscopy,spectroscopy,lithography,X-ray tubes,microwave devices,and data displays.However,the instability in emission current and requirement of ul...Electric field-induced point electron source is highly demanded for microscopy,spectroscopy,lithography,X-ray tubes,microwave devices,and data displays.However,the instability in emission current and requirement of ultrahigh vacuum have often limited its extensive applications.Herewith we report a single-crystalline HfC nanowire with oxycarbide emission surface for stable electron emission at 50 nA with fluctuations less than 1%in a vacuum of 4×10^−7 Pa.The emitter has a low work function of 2.5 eV measured by the field emission Fowler-Nordheim curve and it is in good agreement with density functional theory(DFT)calculations.The energy spread is in a range of 0.21–0.26 eV with a corresponding reduced brightness 1.95×10^11−3.81×10^11 A·m^−2·sr^−1·V^−1.The HfC nanowire with oxycarbide emission surface is a qualified candidate for the next-generation electron source with high brightness,large current,and low energy spread.展开更多
Early years Professor Ke Hsin Kuo was bom in Beijing in 1923,and his childhood was spent in Harbin in northemstem China where his father worked as an engineer to build the local railroad.His early education was at bes...Early years Professor Ke Hsin Kuo was bom in Beijing in 1923,and his childhood was spent in Harbin in northemstem China where his father worked as an engineer to build the local railroad.His early education was at best characterized by frequent disruptions,the first of which being the"9.18 Incidenf of 1931 when the Japanese Kwantung Army launched an assault in Shenyang(Mukden)on the local Chinese troops and quickly took control of all the Northeastern Provinces(Manchuria).He moved to Tianjin in the spring of 1936,where he continued his education by enrolling in the famous Nankai High School.However,his school life at Nankai was soon disrupted again by the eruption of full-scale war in July of 1937 after Japan attacked and occupied Peking.Together with his brothers,he fled to join his parents who had previously relocated to Chongqing.He studied in Chongqing for four more years to complete his high school education,during which classes were constantly being disrupted due to the frequent bombings of the city by Japanese airplanes.These bombings not only left him with long lasting memories of the war,but also bore him a permanent burn scar on his back as a result of a bomb that exploded just meters away from him.展开更多
基金This work was supported partially by the NIMS-DENKA Centre of Excellence for Next Generation MaterialsA part of this work was also supported by NIMS Microstructural Characterization Platform as a program of“Nanotechnology Platform”of the Ministry of Education,Culture,Sports,Science and Technology(MEXT),Japan.
文摘Electric field-induced point electron source is highly demanded for microscopy,spectroscopy,lithography,X-ray tubes,microwave devices,and data displays.However,the instability in emission current and requirement of ultrahigh vacuum have often limited its extensive applications.Herewith we report a single-crystalline HfC nanowire with oxycarbide emission surface for stable electron emission at 50 nA with fluctuations less than 1%in a vacuum of 4×10^−7 Pa.The emitter has a low work function of 2.5 eV measured by the field emission Fowler-Nordheim curve and it is in good agreement with density functional theory(DFT)calculations.The energy spread is in a range of 0.21–0.26 eV with a corresponding reduced brightness 1.95×10^11−3.81×10^11 A·m^−2·sr^−1·V^−1.The HfC nanowire with oxycarbide emission surface is a qualified candidate for the next-generation electron source with high brightness,large current,and low energy spread.
文摘Early years Professor Ke Hsin Kuo was bom in Beijing in 1923,and his childhood was spent in Harbin in northemstem China where his father worked as an engineer to build the local railroad.His early education was at best characterized by frequent disruptions,the first of which being the"9.18 Incidenf of 1931 when the Japanese Kwantung Army launched an assault in Shenyang(Mukden)on the local Chinese troops and quickly took control of all the Northeastern Provinces(Manchuria).He moved to Tianjin in the spring of 1936,where he continued his education by enrolling in the famous Nankai High School.However,his school life at Nankai was soon disrupted again by the eruption of full-scale war in July of 1937 after Japan attacked and occupied Peking.Together with his brothers,he fled to join his parents who had previously relocated to Chongqing.He studied in Chongqing for four more years to complete his high school education,during which classes were constantly being disrupted due to the frequent bombings of the city by Japanese airplanes.These bombings not only left him with long lasting memories of the war,but also bore him a permanent burn scar on his back as a result of a bomb that exploded just meters away from him.
