Bruce Arthur Joyce. 17 October 1934—22 February 2023

Bruce Joyce was internationally renowned in chemistry, physics, materials science and electrical engineering. He is known for his pioneering work in epitaxy, the process during which a crystal is formed on an underlying crystalline surface as the result of deposition of new material. Bruce developed the method, now known as molecular beam epitaxy, to deposit atoms or simple molecules ballistically onto a surface. He also initiated the in situ methods of modulated-beam mass spectroscopy for investigating reaction kinetics and surface electron scattering for measuring the progress of a growing surface at the submonolayer level. Both methods elucidated the fundamental kinetics of the growth process and enabled the growth of semiconductor thin films with unprecedented levels of precision and control. This method opened the way to studies of fundamental physics and to applications of quantum wells. As director of the Interdisciplinary Research Centre for Semiconductor Materials at Imperial College London, Bruce broadened the scope of his interests in the collaborative opportunities offered by the Centre. Among the many projects Bruce initiated were fundamental studies of reflection high-energy electron diffraction (RHEED), scanning tunnelling microscopy for imaging the early stages of growth, using RHEED and transmission electron microscopy to image misfit dislocations during heteroepitaxy, and establishing a correspondence between RHEED and reflectance anisotropy.