Equipment Grant: Superconducting Magnet System for Characterization of New Materials and Devices

磁输运测量已被证明是表征先进半导体材料和器件的最有力的方法之一。该测量可以提供关于材料和器件的大量信息，例如载流子迁移率、载流子密度、电子和空穴的有效质量、弹性和非弹性散射长度、声子发射、栅电容、层厚度等。为了在明尼苏达大学电机系建立这一重要的表征能力，我们建议购买超导磁体系统(SMS)，它由最大磁场为9特斯拉的超导磁体和最低冷却温度为1.5K的低温恒温器组成。这样的短信不仅是必要的，而且对我们目前正在积极进行的针对未来电子产品的人工构造新半导体材料和器件的研究计划也是非常关键的。目前，我系在半导体材料和器件领域共有10名教职员工，其中至少有5名教职员工非常需要利用磁输运表征进行研究。利用方案中要求的磁体系统，我们将测量分子束外延生长的人工结构晶体中电子和空穴的有效质量；我们将研究由分子束外延和超高分辨率电子束光刻制造的各种基于量子效应的新型半导体器件的输运；我们将研究人工结构材料中的应变对电子和空穴的输运特性以及对半导体器件性能的影响；我们还将对增量掺杂分子束外延生长的薄膜进行表征。毫无疑问，不仅是明尼苏达大学电机系列出的研究，而且还有许多其他相关的研究，都可以从获得这个磁体系统中受益匪浅。

Magneto-transport measurement has been proven as one of the most powerful methods in charactering advanced semiconductor materials and devices. The measurement can provide vast information about a material and a device, such as carrier mobility, carrier density, effective mass of electrons and holes, elastic and inelastic scattering lengths, phonon emissions, gate capacitance, layer thicknesses, etc. To establish this important characterization capability in Department of Electrical Engineering at University of Minnesota, we propose to purchase a superconducting magnet system (SMS), which consists of a superconducting magnet of the maximum fields of 9 Tesla and a cryostat of the lowest cooling temperature of 1.5K. Such SMS is not only necessary, but also very crucial to our current vigorous ongoing research program on artificially structured new semiconductor materials and devices for future electronics. Currently, our department has total 10 faculty members in the area of semiconductor materials and devices; and at least five of them have great need of using magneto-transport characterization for their research. With a magnet system requested in the proposal, we will measure the effective mass of electrons and holes in artificially structured crystals grown by MBE; we will study the transport in various new quantum-effect-based semiconductor devices fabricated by MBE and ultra-high resolution e-beam lithography; we will investigate the effect of strain in the artificially structured materials on the transport properties of electrons and holes, and on the performance of semiconductor devices; and we will characterize the delta doped MBE grown films. Undoubtedly, not only the listed research but also many other related research in Department of Electrical Engineering at University of Minnesota can benefit greatly from getting this magnet system.