Answer
GaAs, or gallium arsenide, was the technology researched by Atalla at HP. GaAs is a compound semiconductor material with properties that make it useful in high-speed electronic devices and optoelectronic devices such as lasers and light-emitting diodes. Atalla's research at HP focused on the development of GaAs-based transistors and integrated circuits, which have applications in high-performance computing, telecommunications, and other electronic systems.