His research focuses on the physics of semiconductor materials, in particular for light emitting and sensing applications.

He has contributed to growth and characterization of photovoltaic materials, to the development of materials for optoelectronic applications and of high-resolution transmission electron microscopy. He has co-authored more than 200 papers and eight patents; and has co-edited nine books. He has been involved in promoting science in Latin America, where he has participated in the organization of several international meetings. He was meeting chair of the 1999 Fall MRS Meeting, and chair of the 27th International Conference on the Physics of Semiconductors held in Arizona in 2004. His current interest is in the understanding of the materials properties of III-V nitrides, and their correlation to growth and to device performance for solid state lighting. He is a fellow of the American Physical Society. Since 1999, he has been at the Department of Physics at Arizona State University.