Aligned graphene nanoribbon (GNR) arrays have been made by unzipping of aligned single-walled and few-walled carbon nanotube (CNT) arrays. Nanotube unzipping was achieved by a polymer-protected Ar plasma etching metho...Aligned graphene nanoribbon (GNR) arrays have been made by unzipping of aligned single-walled and few-walled carbon nanotube (CNT) arrays. Nanotube unzipping was achieved by a polymer-protected Ar plasma etching method, and the resulting nanoribbon array can be transferred onto any chosen substrate. Atomic force microscope (AFM) imaging and Raman mapping on the same CNTs before and after unzipping confirmed that ~80% of CNTs were opened up to form single layer sub-10 nm GNRs. Electrical devices made from the GNRs (after annealing in H2 at high temperature) showed on/off current (Ion/Ioff) ratios up to 103 at room temperature, suggesting the semiconducting nature of the narrow GNRs. Novel GNR-GNR and GNR-CNT crossbars were fabricated by transferring GNR arrays across GNR and CNT arrays, respectively. The production of such ordered graphene nanoribbon architectures may allow for large scale integration of GNRs into nanoelectronics or optoelectronics.展开更多
Engineering high‐performance and low‐cost bifunctional catalysts for H_(2)(hydrogen evolution reaction[HER])and O_(2)(oxygen evolution reaction[OER])evolution under industrial electrocatalytic conditions remains cha...Engineering high‐performance and low‐cost bifunctional catalysts for H_(2)(hydrogen evolution reaction[HER])and O_(2)(oxygen evolution reaction[OER])evolution under industrial electrocatalytic conditions remains challenging.Here,for the first time,we use the stronger electronegativity of a rare‐Earth yttrium ion(Y^(3+))to induce in situ NiCo‐layered double‐hydroxide nanosheets from NiCo foam(NCF)treated by a dielectric barrier discharge plasma NCF(PNCF),and then obtain nitrogen‐doped YNiCo phosphide(N‐YNiCoP/PNCF)after the phosphating process using radiofrequency plasma in nitrogen.The obtained NYNiCoP/PNCF has a large specific surface area,rich heterointerfaces,and an optimized electronic structure,inducing high electrocatalytic activity in HER(331mV vs.2000mA cm^(−2))and OER(464mV vs.2000mA cm^(−2))reactions in 1MKOH electrolyte.X‐ray absorption spectroscopy and density functional theory quantum chemistry calculations reveal that the coordination number of CoNi decreased with the incorporation of Y atoms,which induce much shorter bonds of Ni and Co ions and promote long‐term stability of N‐YNiCoP in HER and OER under the simulated industrial conditions.Meanwhile,the CoN‐YP_(5)heterointerface formed by plasma N‐doping is the active center for overall water splitting.This work expands the applications of rare‐Earth elements in engineering bifunctional electrocatalysts and provides a new avenue for designing highperformance transition‐metal‐based catalysts in the renewable energy field.展开更多
A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etc...A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.展开更多
基金This work was supported by MARCO-MSD,Intel,ONR and graphene-MURI.
文摘Aligned graphene nanoribbon (GNR) arrays have been made by unzipping of aligned single-walled and few-walled carbon nanotube (CNT) arrays. Nanotube unzipping was achieved by a polymer-protected Ar plasma etching method, and the resulting nanoribbon array can be transferred onto any chosen substrate. Atomic force microscope (AFM) imaging and Raman mapping on the same CNTs before and after unzipping confirmed that ~80% of CNTs were opened up to form single layer sub-10 nm GNRs. Electrical devices made from the GNRs (after annealing in H2 at high temperature) showed on/off current (Ion/Ioff) ratios up to 103 at room temperature, suggesting the semiconducting nature of the narrow GNRs. Novel GNR-GNR and GNR-CNT crossbars were fabricated by transferring GNR arrays across GNR and CNT arrays, respectively. The production of such ordered graphene nanoribbon architectures may allow for large scale integration of GNRs into nanoelectronics or optoelectronics.
基金National Natural Science Foundation of China,Grant/Award Number:52177162the Natural Science Foundation of Zhejiang Province,Grant/Award Numbers:LZ22E070003,LQ22E020006+1 种基金the Funding Project for Academic/Technical Leaders of Jiangxi Province,Grant/Award Number:20225BCJ22003the Natural Science Foundation of Jiangxi Province,Grant/Award Number:20212ACB211001。
文摘Engineering high‐performance and low‐cost bifunctional catalysts for H_(2)(hydrogen evolution reaction[HER])and O_(2)(oxygen evolution reaction[OER])evolution under industrial electrocatalytic conditions remains challenging.Here,for the first time,we use the stronger electronegativity of a rare‐Earth yttrium ion(Y^(3+))to induce in situ NiCo‐layered double‐hydroxide nanosheets from NiCo foam(NCF)treated by a dielectric barrier discharge plasma NCF(PNCF),and then obtain nitrogen‐doped YNiCo phosphide(N‐YNiCoP/PNCF)after the phosphating process using radiofrequency plasma in nitrogen.The obtained NYNiCoP/PNCF has a large specific surface area,rich heterointerfaces,and an optimized electronic structure,inducing high electrocatalytic activity in HER(331mV vs.2000mA cm^(−2))and OER(464mV vs.2000mA cm^(−2))reactions in 1MKOH electrolyte.X‐ray absorption spectroscopy and density functional theory quantum chemistry calculations reveal that the coordination number of CoNi decreased with the incorporation of Y atoms,which induce much shorter bonds of Ni and Co ions and promote long‐term stability of N‐YNiCoP in HER and OER under the simulated industrial conditions.Meanwhile,the CoN‐YP_(5)heterointerface formed by plasma N‐doping is the active center for overall water splitting.This work expands the applications of rare‐Earth elements in engineering bifunctional electrocatalysts and provides a new avenue for designing highperformance transition‐metal‐based catalysts in the renewable energy field.
文摘A study of Cl2/BCl3-based inductively coupled plasma （ICP） was conducted using thick photoresist mask for anisotropic etching of 50μm diameter holes in a GaAs wafer at a relatively high average etching rate for etching depths of more than 150μm. Plasma etch characteristics with ICP process pressure and the percentage of BCI3 were studied in greater detail at a constant ICP coil/bias power. The measured peak-to-peak voltage as a function of pressure was used to estimate the minimum energy of the ions bombarding the substrate. The process pressure was found to have a substantial influence on the energy of heavy ions. Various ion species in plasma showed minimum energy variation from 1.85 eV to 7.5 eV in the pressure range of 20 mTorr to 50 mTorr. The effect of pressure and the percentage of BCl3 on the etching rate and surface smoothness of the bottom surface of the etched hole were studied for a fixed total flow rate. The etching rate was found to decrease with the percentage of BCl3, whereas the addition of BCl3 resulted in anisotropic holes with a smooth veil free bottom surface at a pressure of 30 mTorr and 42% BC13. In addition, variation of the etching yield with pressure and etching depth were also investigated.
