MRI: Development of a Combination High Resolution and Low Current Density Inverse Photoemission Spectrograph for Research and Eduction

MRI：开发用于研究和教育的高分辨率和低电流密度逆光电发射光谱仪组合

• 批准号: 0421177
• 负责人: Robert Opila
• 金额: $ 18.98万
• 依托单位: University of Delaware
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-09-01 至 2007-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0421177&HistoricalAwards=false
• 关键词: MRI; Development; Combination; Resolution; Low

Recently, tremendous advances have been achieved in the development of new materials such as highly correlated electron systems, nanoscale materials, organic semiconductors and promising species for molecular electronics. While photoelectron spectroscopy has played a central role in establishing key properties of these materials, there has been markedly less progress towards understanding the spectral function above EF. Inverse photoemission (IPE) spectroscopy is the natural choice for probing this energy range, but high current densities and low energy resolution limit its application to these interesting systems. The proposed instrument will greatly relieve these shortcomings and open to experimental scrutiny the spectral function above the Fermi level of these interesting materials. The information gained from this new instrument will enable intelligent design of candidate species for molecular electronics or organic semiconductor applications. Similarly it will test our current theoretical understanding of highly correlated electron systems by experimentally probing the energy and momentum dependence of the spectral function in a new regime. We will develop and construct the prototype for a new generation of inverse photoemission spectrographs that will serve the dual demands of modern materials science -- low current density and high energy resolution -- while maintaining high count rates. This objective will be achieved by a design principle that exploits the compatibility between a fast (f/5) normal incidence grating spectrograph and the spatially extended linear electron spot produced by either of two sources: a modified, high perveance electron gun, and a high resolution electron energy monochromator. This dual source approach will enable us to perform rapid exploratory measurements and then investigate interesting features either with low current densities (~0.1 mA/mm2) or with high resolution (~ 50 meV) at good count rates (~ 100 Hz). The instruments will serve the research community at the University of Delaware, Rutgers University, and other neighboring institutions. With the proposed instrument, the PI's will add to their strong track record of outreach both within and out of the academic communities, as well as ensure members of underrepresented groups have direct participation in our research activities.The proposed instrument will give previously unattainable experimental access a wide range of problems in modern condensed matter and materials physics, semiconducting organic materials, organic molecular electronics, modern electronics, and superconductivity. This new instrument will probe, with very high energy resolution, the unfilled electronic levels in conducting systems with minimal perturbation of the other charge carriers and minimal damage to the materials system. We propose a program to develop and construct the prototype for a new generation of inverse photoemission spectrographs that will serve the dual demands of modern materials science -- low current density and high energy resolution -- while maintaining high count rates. While traditional photoelectron spectroscopy has played a central role in establishing key properties of the bonding and charge carriers in the filled electronic levels of these materials, there has been markedly less progress towards understanding the unfilled levels. Inverse photoemission (IPE) spectroscopy is the natural choice for probing this energy range, but high current densities and low energy resolution limit its application to these interesting systems. The proposed instrument will greatly relieve these shortcomings. The information gained from this new instrument will enable intelligent design of candidate species for molecular electronics or organic semiconductor applications. Similarly it will test our current theoretical understanding of highly correlated electron systems, for example, superconductors, by experimentally probing the energy and momentum dependence of the spectral function in a new regime. The instruments will serve the research community at the University of Delaware, Rutgers University, and other neighboring institutions. With the proposed instrument, the PI's will add to their strong track record of outreach both within and out of the academic communities, as well as ensure members of underrepresented groups have direct participation in our research activities.

近年来，高关联电子系统、纳米材料、有机半导体、分子电子学等新材料的发展取得了巨大的进展。虽然光电子能谱在确定这些材料的关键性质方面发挥了核心作用，但在理解EF以上的光谱函数方面取得的进展明显较少。逆光电子能谱(IPE)是探测这一能量范围的自然选择，但高电流密度和低能量分辨率限制了它在这些有趣的体系中的应用。所提出的仪器将极大地克服这些缺点，并对这些有趣材料的费米能级以上的光谱函数进行实验研究。从这一新仪器获得的信息将使分子电子或有机半导体应用的候选物种的智能设计成为可能。同样，它将通过实验探索光谱函数在新区域内的能量和动量依赖关系，来检验我们目前对高度关联电子系统的理论理解。我们将开发和建造新一代反向光电发射光谱仪的原型，以满足现代材料科学的双重需求--低电流密度和高能量分辨率--同时保持高计数率。这一目标将通过一种设计原则来实现，该设计原理利用快速(f/5)垂直入射光栅光谱仪与由两个源中的任何一个产生的空间扩展的线性电子点之间的兼容性：改进的高导电率电子枪和高分辨率电子能量单色仪。这种双源方法将使我们能够执行快速探索性测量，然后在低电流密度(~0.1 mA/mm2)或高分辨率(~50 meV)、良好的计数速率(~100赫兹)下研究有趣的特征。这些仪器将服务于特拉华大学、罗格斯大学和其他邻近机构的研究社区。有了拟议的仪器，PI将增加他们在学术界内外的良好记录，并确保未被充分代表的团体的成员直接参与我们的研究活动。拟议的仪器将使以前无法实现的实验访问现代凝聚态和材料物理、半导体有机材料、有机分子电子学、现代电子学和超导等领域的广泛问题。这台新仪器将以非常高的能量分辨率探测导电系统中未填充的电子能级，对其他载流子的扰动最小，对材料系统的损害也最小。我们提出了一个计划来开发和构建新一代反向光电发射光谱仪的原型，该原型将服务于现代材料科学的双重需求--低电流密度和高能量分辨率--同时保持高计数率。虽然传统的光电子能谱在确定这些材料的填充电子能级中的键和电荷载流子的关键性质方面发挥了核心作用，但在理解未填充电子能级方面的进展明显较少。逆光电子能谱(IPE)是探测这一能量范围的自然选择，但高电流密度和低能量分辨率限制了它在这些有趣的体系中的应用。拟议的文书将极大地弥补这些缺点。从这一新仪器获得的信息将使分子电子或有机半导体应用的候选物种的智能设计成为可能。同样，它将通过实验探索光谱函数在新区域内的能量和动量依赖关系，来检验我们目前对高度关联电子系统，例如超导体的理论理解。这些仪器将服务于特拉华大学、罗格斯大学和其他邻近机构的研究社区。有了拟议的工具，国际和平协会将增加他们在学术界内外的良好外联记录，并确保代表性不足的群体的成员直接参与我们的研究活动。