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
Simultaneously improving the efficiency and stability on a large scale is significant for the development of photoelectrochemical(PEC)water splitting systems.Here,we demonstrated a novel design of GaP/GaPN core/shell ...Simultaneously improving the efficiency and stability on a large scale is significant for the development of photoelectrochemical(PEC)water splitting systems.Here,we demonstrated a novel design of GaP/GaPN core/shell nanowire(NW)decorated p-Si photocathode for improved PEC hydrogen production performance compared to that of bare p-Si photocathode.The formation of the p-n junction between p-Si and GaP NW promotes charge separation,and the lower conduction band position of GaPN relative to that of GaP further facilitates the transfer of photogenerated electrons to the electrode surface.In addition,the NW morphology both shortens the carrier collection distance and increases the specific surface area,which result in superior reaction kinetics.Moreover,introduction of N in GaP is beneficial for enhancing the light absorption as well as stability.Our efficient and facile strategy can be applied to other solar energy conversion systems as well.展开更多
The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructur...The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructure by combining a facile hydrothermal method and subsequent controlled oxidation process. The fine structure and epitaxial relationship between the branches and backbone are investigated by high-resolution transmission electron microscopy. Moreover, the evolution of the branch growth has also been observed during the gradual oxidation of the Cu nanowire surface. The experimental results suggest that the surface oxidation needs to be performed via a two-step exposure process to varying humidity in order to achieve optimized formation of a core-shell structured branching architecture. Finally, a proof-of-concept of the function of such a hierarchical framework as the anode material in lithium-ion batteries is demonstrated. The branching core-shell heterostructure improves battery performance by several means： （i） The epitaxially grown branches provide a high surface area for enhanced electrolyte accessibility and high resistance to volume change induced by Li^＋ intercalation/extraction; （ii） the core-shell structure with its well-defined heterojunction increases the contact area which facilitates effective charge transport during lithiation; （iii） the copper core acts as a current collector as well as providing structural reinforcement.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financial support for this work from the National Natural Science Foundation of China (21422303, 21573049, 21872043, 81602643)Beijing Natural Science Foundation (2142036)+1 种基金Youth Innovation Promotion AssociationSpecial Program of “One Belt One Road” of CAS~~
文摘Simultaneously improving the efficiency and stability on a large scale is significant for the development of photoelectrochemical(PEC)water splitting systems.Here,we demonstrated a novel design of GaP/GaPN core/shell nanowire(NW)decorated p-Si photocathode for improved PEC hydrogen production performance compared to that of bare p-Si photocathode.The formation of the p-n junction between p-Si and GaP NW promotes charge separation,and the lower conduction band position of GaPN relative to that of GaP further facilitates the transfer of photogenerated electrons to the electrode surface.In addition,the NW morphology both shortens the carrier collection distance and increases the specific surface area,which result in superior reaction kinetics.Moreover,introduction of N in GaP is beneficial for enhancing the light absorption as well as stability.Our efficient and facile strategy can be applied to other solar energy conversion systems as well.
基金We thank Prof. Mingbo Wu （State Key Laboratory of Heavy Oil Processing, China University of Petroleum） for his help in experiments. This work was finandally supported by the Key Joint Foundation of PetroChina, the National Natural Science Foundation of China （Nos. 51271215, U1362202, and 21106185） and the PetroChina Key Programs on Oil Refinery Catalysts （No. 2010E-1908 and 2010E-1903）.
文摘The careful design of nano-architectures and smart hybridization of expected active materials can lead to more advanced properties. Here we have engineered a novel hierarchical branching Cu/Cu2O/CuO heteronanostructure by combining a facile hydrothermal method and subsequent controlled oxidation process. The fine structure and epitaxial relationship between the branches and backbone are investigated by high-resolution transmission electron microscopy. Moreover, the evolution of the branch growth has also been observed during the gradual oxidation of the Cu nanowire surface. The experimental results suggest that the surface oxidation needs to be performed via a two-step exposure process to varying humidity in order to achieve optimized formation of a core-shell structured branching architecture. Finally, a proof-of-concept of the function of such a hierarchical framework as the anode material in lithium-ion batteries is demonstrated. The branching core-shell heterostructure improves battery performance by several means： （i） The epitaxially grown branches provide a high surface area for enhanced electrolyte accessibility and high resistance to volume change induced by Li^＋ intercalation/extraction; （ii） the core-shell structure with its well-defined heterojunction increases the contact area which facilitates effective charge transport during lithiation; （iii） the copper core acts as a current collector as well as providing structural reinforcement.
