Instrumentation for RHEED Pole Figure

Abstract

In this chapter, we describe the major reflection high-energy electron diffraction (RHEED) hardware components: a vacuum system, an electron gun, a sample manipulator, a step motor, a phosphor screen, and a charge-coupled device camera. Most molecular beam epitaxy (MBE) laboratories with in situ RHEED characterization capability are equipped with this hardware. We discuss what has been learned from past practices on issues such as minimization of sample wobbling during rotation and sample size required due to glancing incidence angle of the electron beam. Data collection and step-by-step operational procedures are described in Appendix A. Data processing program codes developed for RHEED pole figure construction are also given in Appendix A. With this hardware and software, one can perform RHEED experiments in the transmission mode and construct RHEED pole figures to study the sample’s textures. We highlight the RHEED instrument response function for reflection and transmission modes for quantitative analysis of texture dispersions. We also discuss the part of the instrument response function for transmission mode diffracted from rough surfaces that does not exist in the instrument response function of the reflection mode.