Various methods for production of polysilicon have been proposed for lowering the production cost andenergy consumption, and enhancing productivity, which are critical for industrial applications. The fluidized bed ch...Various methods for production of polysilicon have been proposed for lowering the production cost andenergy consumption, and enhancing productivity, which are critical for industrial applications. The fluidized bed chemical vapor deposition （FBCVD） method is a most promising alternative to conventional ones, but the homogeneous reaction of silane in FBCVD results in unwanted formation of fines, which will affect the product qualityand output. There are some other problems, such as heating degeneration due to undesired polysilicon deposition on the walls of the reactor and the heater. This article mainly reviews the technological development on FBCVD of polycrystalline silicon and the research status for solving the above problems. It also identifies a number of challenges to tackle and principles should be followed in the design ofa FBCVD reactor.展开更多
Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which ...Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which greatly limited the rate of the nucleation and the sequent growth. The emerging liquid metal catalyst possesses the characteristic of quasi-atomically smooth surface with high diffusion rate. In principle, it should be a naturally ideal platform for the lowdensity nucleation and the fast growth of graphene. However,the rapid growth of large graphene single crystals on liquid metals has not received the due attention. In this paper, we firstly purposed the insight into the rapid growth of large graphene single crystals on liquid metals. We obtained the millimeter-size graphene single crystals on liquid Cu. The rich free-electrons in liquid Cu accelerate the nucleation, and the isotropic smooth surface greatly suppresses the nucleation.Moreover, the fast mass-transfer of carbon atoms due to the excellent fluidity of liquid Cu promotes the fast growth with a rate up to 79 μm s^-1. We hope the research on the growth speed of graphene on liquid Cu can enrich the recognition of the growth behavior of two-dimensional(2 D) materials on the liquid metal. We also believe that the liquid metal strategy for the rapid growth of graphene can be extended to various 2 D materials and thus promote their future applications in the photonics and electronics.展开更多
In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon o...In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon oxide） by plasma-enhanced chemical vapor deposition method. The influence of the n-μc-SiOx：H emitter thickness on the heterointerface passivation in SHJ solar cells was investi- gated. With increasing thickness, the crystallinity of the emitter as well as its dark conductivity increases. Mean- while, the effective minority carrier lifetime （teff） of the SHJ solar cell precursors at low injection level shows a pronounced increase trend, implying that an improved field effect passivation is introduced as the emitter is deposited. And, an increased μTelf is also observed at entire injection level due to the interfacial chemical passivation improved by the hydrogen diffusion along with the emitter deposition. Based on the analysis on the external quantum effi- ciency of the SHJ solar cells, it can be expected that the high efficient SHJ solar cells could be obtained by improving the heterointerface passivation and optimizing the emitter deposition process.展开更多
Atomically thin solid-state channels enabling selective molecular transport could potentially be used in a variety of separation and energy conversion applications.The density of channels,their height,distance and edg...Atomically thin solid-state channels enabling selective molecular transport could potentially be used in a variety of separation and energy conversion applications.The density of channels,their height,distance and edge structure are the key factors that dramatically impact the selective transport performance.However,such channels with small constrictions and atomic precision have been limited to proof-ofconcept demonstrations based on microscale two-dimensional(2D)crystal stripes.Here,we report the engineering of highly ordered,scalable monolayer graphene crystallite arrays by chemical vapor deposition(CVD)method with a modified anisotropic etching approach.The size,shape,distance and edge structure of the graphene crystallite arrays in a large area could be delicately controlled through tailoring the synthetic parameters.This array structure can act as pillars to prop up a smooth single-crystal graphene film,and the fabricated integrated angstrom-size(3.4A)channels allow water transport but exclude hydrated ions,demonstrating potential in selective ionic sieving and nanofiltration practice.展开更多
基金Supported by the Natural Science Foundation of Shandong Province of China （ZR2009BM011） and the Doctor Foundation of Shandong Province of China （BS2010NJ005）.
文摘Various methods for production of polysilicon have been proposed for lowering the production cost andenergy consumption, and enhancing productivity, which are critical for industrial applications. The fluidized bed chemical vapor deposition （FBCVD） method is a most promising alternative to conventional ones, but the homogeneous reaction of silane in FBCVD results in unwanted formation of fines, which will affect the product qualityand output. There are some other problems, such as heating degeneration due to undesired polysilicon deposition on the walls of the reactor and the heater. This article mainly reviews the technological development on FBCVD of polycrystalline silicon and the research status for solving the above problems. It also identifies a number of challenges to tackle and principles should be followed in the design ofa FBCVD reactor.
基金supported by the National Natural Science Foundation of China(21673161)the Sino-German Center for Research Promotion(1400)
文摘Previous reports about the growth of large graphene single crystals on polycrystalline metal substrates usually adopted the strategy of suppressing the nucleation by lowering the concentration of the feedstock, which greatly limited the rate of the nucleation and the sequent growth. The emerging liquid metal catalyst possesses the characteristic of quasi-atomically smooth surface with high diffusion rate. In principle, it should be a naturally ideal platform for the lowdensity nucleation and the fast growth of graphene. However,the rapid growth of large graphene single crystals on liquid metals has not received the due attention. In this paper, we firstly purposed the insight into the rapid growth of large graphene single crystals on liquid metals. We obtained the millimeter-size graphene single crystals on liquid Cu. The rich free-electrons in liquid Cu accelerate the nucleation, and the isotropic smooth surface greatly suppresses the nucleation.Moreover, the fast mass-transfer of carbon atoms due to the excellent fluidity of liquid Cu promotes the fast growth with a rate up to 79 μm s^-1. We hope the research on the growth speed of graphene on liquid Cu can enrich the recognition of the growth behavior of two-dimensional(2 D) materials on the liquid metal. We also believe that the liquid metal strategy for the rapid growth of graphene can be extended to various 2 D materials and thus promote their future applications in the photonics and electronics.
文摘In this paper, we tion （SHJ） solar cells with prepared silicon heterojunc- the structure of p-c-Si/i-a- SiOx：H/n-μc-SiOx：H （a-SiOx：H, oxygen rich amorphous silicon oxide; μc-SiOx：H, microcrystalline silicon oxide） by plasma-enhanced chemical vapor deposition method. The influence of the n-μc-SiOx：H emitter thickness on the heterointerface passivation in SHJ solar cells was investi- gated. With increasing thickness, the crystallinity of the emitter as well as its dark conductivity increases. Mean- while, the effective minority carrier lifetime （teff） of the SHJ solar cell precursors at low injection level shows a pronounced increase trend, implying that an improved field effect passivation is introduced as the emitter is deposited. And, an increased μTelf is also observed at entire injection level due to the interfacial chemical passivation improved by the hydrogen diffusion along with the emitter deposition. Based on the analysis on the external quantum effi- ciency of the SHJ solar cells, it can be expected that the high efficient SHJ solar cells could be obtained by improving the heterointerface passivation and optimizing the emitter deposition process.
基金the National Natural Science Foundation of China(51772110,61890940)。
文摘Atomically thin solid-state channels enabling selective molecular transport could potentially be used in a variety of separation and energy conversion applications.The density of channels,their height,distance and edge structure are the key factors that dramatically impact the selective transport performance.However,such channels with small constrictions and atomic precision have been limited to proof-ofconcept demonstrations based on microscale two-dimensional(2D)crystal stripes.Here,we report the engineering of highly ordered,scalable monolayer graphene crystallite arrays by chemical vapor deposition(CVD)method with a modified anisotropic etching approach.The size,shape,distance and edge structure of the graphene crystallite arrays in a large area could be delicately controlled through tailoring the synthetic parameters.This array structure can act as pillars to prop up a smooth single-crystal graphene film,and the fabricated integrated angstrom-size(3.4A)channels allow water transport but exclude hydrated ions,demonstrating potential in selective ionic sieving and nanofiltration practice.
