采用 Al N插入层技术在 Si(1 1 1 )衬底上实现无微裂 Ga N MOCVD生长 .通过对 Ga N外延层的 a,c轴晶格常数的测量 ,得到了 Ga N所受张应力与 Al N插入层厚度的变化关系 .当 Al N厚度在 7～ 1 3nm范围内 ,Ga N所受张应力最小 ,甚至变为...采用 Al N插入层技术在 Si(1 1 1 )衬底上实现无微裂 Ga N MOCVD生长 .通过对 Ga N外延层的 a,c轴晶格常数的测量 ,得到了 Ga N所受张应力与 Al N插入层厚度的变化关系 .当 Al N厚度在 7～ 1 3nm范围内 ,Ga N所受张应力最小 ,甚至变为压应力 .因此 ,Ga N微裂得以消除 .同时研究了 Al N插入层对 Ga N晶体质量的影响 ,结果表明 ,许多性能相比于没有 Al N插入层的 Ga展开更多
Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are n...Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.展开更多
Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane...Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.展开更多
We report a method using in situ etching to decouple the axial from the radial nanowire growth pathway,independent of other growth parameters.Thereby a wide range of growth parameters can be explored to improve the na...We report a method using in situ etching to decouple the axial from the radial nanowire growth pathway,independent of other growth parameters.Thereby a wide range of growth parameters can be explored to improve the nanowire properties without concern of tapering or excess structural defects formed during radial growth.We demonstrate the method using etching by HCl during InP nanowire growth.The improved crystal quality of etched nanowires is indicated by strongly enhanced photoluminescence as compared to reference nanowires obtained without etching.展开更多
InGaN quantum dot is a promising optoelectronic material, which combines the advantages of low-dimensional and wide-gap semiconductors. The growth of InGaN quantum dots is still not mature, especially the growth by me...InGaN quantum dot is a promising optoelectronic material, which combines the advantages of low-dimensional and wide-gap semiconductors. The growth of InGaN quantum dots is still not mature, especially the growth by metal--organic- vapor phase epitaxy （MOVPE）, which is challenge due to the lack of, itin-situ monitoring tool. In this paper, we reviewed the development of InGaN quantum dot growth by MOVPE, including our work on growth of near-UV, green, and red InGaN quantum dots. In addition, we also introduced the applications of InGaN quantum dots on visible light emitting diodes.展开更多
文摘采用 Al N插入层技术在 Si(1 1 1 )衬底上实现无微裂 Ga N MOCVD生长 .通过对 Ga N外延层的 a,c轴晶格常数的测量 ,得到了 Ga N所受张应力与 Al N插入层厚度的变化关系 .当 Al N厚度在 7～ 1 3nm范围内 ,Ga N所受张应力最小 ,甚至变为压应力 .因此 ,Ga N微裂得以消除 .同时研究了 Al N插入层对 Ga N晶体质量的影响 ,结果表明 ,许多性能相比于没有 Al N插入层的 Ga
文摘Position controlled nanowire growth is important for nanowire-based optoelectronic components which rely on light emission or light absorption. For solar energy harvesting applications, dense arrays of nanowires are needed; however, a major obstacle to obtaining dense nanowire arrays is seed particle displacement and coalescing during the annealing stage prior to nanowire growth. Here, we explore three different strategies to improve pattern preservation of large-area catalyst particle arrays defined by nanoimprint lithography for nanowire growth. First, we see that heat treating the growth substrate prior to nanoimprint lithography improves pattern preservation. Second, we explore the possibility of improving pattern preservation by fixing the seed particles in place prior to annealing by modifying the growth procedure. And third, we show that a SiNx growth mask can fully prevent seed particle displacement. We show how these strategies allow us to greatly improve the pattern fidelity of grown InP nanowire arrays with dimensions suitable for solar cell applications, ultimately achieving 100% pattern preservation over the sampled area. The generic nature of these strategies is supported through the synthesis of GaAs and GaP nanowires.
基金the National Key Research and Development Program(2021YFA0716400)the National Natural Science Foundation of China(62225405,62350002,61991443)+1 种基金the Key R&D Project of Jiangsu Province,China(BE2020004)the Collaborative Innovation Centre of Solid-State Lighting and Energy-Saving Electronics.
文摘Growth of gallium nitride(GaN)inverted pyramids on c-plane sapphire substrates is benefit for fabricating novel devices as it forms the semipolar facets.In this work,GaN inverted pyramids are directly grown on c-plane patterned sapphire substrates(PSS)by metal organic vapor phase epitaxy(MOVPE).The influences of growth conditions on the surface morphol-ogy are experimentally studied and explained by Wulff constructions.The competition of growth rate among{0001},{1011},and{1122}facets results in the various surface morphologies of GaN.A higher growth temperature of 985 ℃ and a lowerⅤ/Ⅲratio of 25 can expand the area of{}facets in GaN inverted pyramids.On the other hand,GaN inverted pyramids with almost pure{}facets are obtained by using a lower growth temperature of 930℃,a higherⅤ/Ⅲratio of 100,and PSS with pattern arrangement perpendicular to the substrate primary flat.
基金This work was performed within the Nanometer Structure Consortium at Lund University and supported by the Swedish Energy Agency,the Swedish Research Council,the Swedish Foundation for Strategic Research,and by the EU programs AMON-RA(No.214814)and NODE(No.015783)This report is based on a project which was funded by E.ON AG as part of the E.ON International Research Initiative.Responsibility for the content of this publication lies with the authors.
文摘We report a method using in situ etching to decouple the axial from the radial nanowire growth pathway,independent of other growth parameters.Thereby a wide range of growth parameters can be explored to improve the nanowire properties without concern of tapering or excess structural defects formed during radial growth.We demonstrate the method using etching by HCl during InP nanowire growth.The improved crystal quality of etched nanowires is indicated by strongly enhanced photoluminescence as compared to reference nanowires obtained without etching.
基金Project supported by the National Basic Research Program of China(Grant Nos.2013CB632804,2011CB301900,and 2012CB3155605)the National Natural Science Foundation of China(Grant Nos.61176015,61210014,51002085,61321004,61307024,and 61176059)the High Technology Research and Development Program of China(Grant No.2012AA050601)
文摘InGaN quantum dot is a promising optoelectronic material, which combines the advantages of low-dimensional and wide-gap semiconductors. The growth of InGaN quantum dots is still not mature, especially the growth by metal--organic- vapor phase epitaxy （MOVPE）, which is challenge due to the lack of, itin-situ monitoring tool. In this paper, we reviewed the development of InGaN quantum dot growth by MOVPE, including our work on growth of near-UV, green, and red InGaN quantum dots. In addition, we also introduced the applications of InGaN quantum dots on visible light emitting diodes.
