Hall Effect in a Semiconductor

本计画系建构一个实验来量测半导体晶体的霍耳效应。这个实验取代了目前的实验来测量霍尔效应的等离子体，这是严重限制了学生无法准确地评估他们的数据，在没有等离子体流体力学的理解。在半导体霍尔效应实验中，学生测量锗晶体的电阻率和霍尔电压，当磁场横向于通过晶体的电流施加时，霍尔电压产生。在液氮和室温之间的各种温度下进行这些测量，学生们确定锗的带隙值，晶体中杂质的密度，电阻率和电子和空穴迁移率的温度依赖性，以及磁阻对温度和外加磁场的依赖性。通过霍尔效应实验，学生不仅扩展了半导体物理基础知识，而且更好地了解现代凝聚态研究中使用的技术。他们学习如何测量和控制液氮和高于室温的温度之间的温度，以及如何在材料中进行电气测量，包括零测量。实验还提高了他们的数据简化和分析技能。

This project is constructing an experiment to measure the Hall effect in a semiconductor crystal. This experiment replaces the current experiment to measure the Hall effect in a plasma, which is seriously limited by the inability of students to evaluate their data accurately in the absence of an understanding of plasma hydrodynamics. In the Hall effect in a semiconductor experiment students make measurements of the resistivity of a germanium crystal and the Hall voltage that develops when a magnetic field is applied transverse to the applied current through the crystal. Taking these measurements at a variety of temperatures between liquid nitrogen and room temperatures, the students determine the value of the band gap in germanium, the density of impurities in the crystal, the temperature dependence of the resistivity and the electron and hole mobilities, and the dependence of the magnetoresistance on temperature and applied magnetic field. Through the Hall effect experiment, students not only extend their knowledge of the fundamentals of semiconductor physics but also become better acquainted with the techniques used in modern condensed matter research. They learn how to measure and control temperatures between liquid nitrogen and higher than room temperatures and how to make electrical measurements, including null measurements, in materials. The experiment also improves their data reduction and analysis skills.