Materials World Network: Detached Bridgman Growth of Semiconductor Crystals

This effort is based on collaboration between research groups at the University of Minnesota (UMN) and the Albert-Ludwigs-Universitaet (ALU) in Freiburg, Germany. The research focuses on a novel crystal growth technique, the Detached Bridgman process, that originated in early microgravity experiments conducted during the first Skylab missions (1974). By eliminating deleterious interactions between the growing crystal and the ampoule wall, this method is capable of producing crystals with unprecedented levels of structural perfection; however, detached solidification has not yet been reliably implemented on earth. The combined experimental work at ALU and theoretical research at UMN will aim to make this process viable under terrestrial growth conditions. An important part of this joint project focuses on student exchanges that will train graduate students in both crystal growth theory and practice and will provide them with international experiences that will encourage them to become leaders in the global materials research community of tomorrow.

This activity teams two of the foremost crystal growth groups in the world to leverage their strongly complementary skills toward the realization and transformative potential of detached solidification. Experiments and theory will be conducted with complementary goals; the effort at UMN brings crystal growth modeling tools and expertise with significant computational resources available from the Minnesota Supercomputing Institute, and the ALU experimental effort leverages their mastery and state-of-the-art infrastructure for crystal growth, along with 10 years of experience with detached growth on earth and in space. Enabling the detached Bridgman process promises a means to produce large, single crystals of compound semiconductors with quality heretofore unattainable. Initial efforts will focus on growing the II-VI semiconductor cadmium zinc telluride, a material needed for high-sensitivity radiation detectors that are of great strategic importance for nuclear nonproliferation applications and securing national borders.