GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nan...GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.展开更多
Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method ...Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method to fabricate a series of core@shell Ni@RuM(M=Ni or Co)nanocrystals(NCs)with Ni as the core and tunable RuM(M=Ni or Co)as the alloy shell for efficient water-splitting catalysis.Among these core@shell NCs,the obtained Ni@Ru Ni NCs exhibit the highest intrinsic activity for hydrogen evolution reaction(HER)and possess an outstanding mass activity of 1590 m A mgRu^-1 at 0.07 V vs.reversible hydrogen electrode(RHE),which is 1.7 times higher than that of commercial Pt/C(950 m A mgPt^-1).As for oxygen evolution reaction(OER),the prepared Ni@Ru0.4 Co0.6 NCs with optimized shell composition achieve more enhanced mass activity of 270 m A mgRu^-1 at1.56 V vs.RHE,approaching three times higher than that of commercial RuO2(89 m A mgRu^-1).The superb mass activity of these Ni@Ru M(M=Ni or Co)NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell.展开更多
文摘GaAs-based nanomaterials are essential for near-infrared nano-photoelectronic devices due to their exceptional optoelectronic properties.However,as the dimensions of GaAs materials decrease,the development of GaAs nanowires(NWs)is hindered by type-Ⅱquantum well structures arising from the mixture of zinc blende(ZB)and wurtzite(WZ)phases and surface defects due to the large surface-to-volume ratio.Achieving GaAs-based NWs with high emission efficiency has become a key research focus.In this study,pre-etched silicon substrates were combined with GaAs/AlGaAs core-shell heterostructure to achieve GaAs-based NWs with good perpendicularity,excellent crystal structures,and high emission efficiency by leveraging the shadowing effect and surface passivation.The primary evidence for this includes the prominent free-exciton emission in the variable-temperature spectra and the low thermal activation energy indicated by the variable-power spectra.The findings of this study suggest that the growth method described herein can be employed to enhance the crystal structure and optical properties of otherⅢ-Ⅴlow-dimensional materials,potentially paving the way for future NW devices.
基金funding from the National Natural Science Foundation of China (21427811, 21721003 and 51671003)the Ministry of Science and Technology, China (2016YFA0203200)+1 种基金the Youth Innovation Promotion Association CAS (2016208)Jilin Province Science Technology Development Plan Project (20170101194JC)
文摘Developing efficient water-splitting electrocatalysts with high mass activity is in urgent need for largescale sustainable production of hydrogen but,still remains as a big challenge.Herein,we report a one-pot method to fabricate a series of core@shell Ni@RuM(M=Ni or Co)nanocrystals(NCs)with Ni as the core and tunable RuM(M=Ni or Co)as the alloy shell for efficient water-splitting catalysis.Among these core@shell NCs,the obtained Ni@Ru Ni NCs exhibit the highest intrinsic activity for hydrogen evolution reaction(HER)and possess an outstanding mass activity of 1590 m A mgRu^-1 at 0.07 V vs.reversible hydrogen electrode(RHE),which is 1.7 times higher than that of commercial Pt/C(950 m A mgPt^-1).As for oxygen evolution reaction(OER),the prepared Ni@Ru0.4 Co0.6 NCs with optimized shell composition achieve more enhanced mass activity of 270 m A mgRu^-1 at1.56 V vs.RHE,approaching three times higher than that of commercial RuO2(89 m A mgRu^-1).The superb mass activity of these Ni@Ru M(M=Ni or Co)NCs can be attributed to their core@shell structure and modulated electronic structure through alloying with Ni or Co metal in the shell.
