US engineers build transistor-like switch for quantum excitons

University of Michigan engineers have developed the first transistor-like switch that can control the flow of excitons—quantum quasiparticles that carry energy without charge—at room temperature. Excitons form when light excites electrons in semiconductors, creating electron-hole pairs that move together as neutral energy packets. Unlike electrons, excitons do not generate heat through energy loss, making them promising candidates for more efficient computing technologies. The team overcame a major challenge by designing a nanostructured ridge that guides excitons along a controlled path and using electrodes as gates to switch exciton flow on and off, achieving an on-off switching ratio above 19 decibels. This breakthrough opens the door to excitonic circuits that could significantly reduce energy consumption and heat generation in computing systems, addressing current limitations faced by electronics in AI and other demanding applications. The researchers also demonstrated an optoexcitonic switch using light to propel excitons rapidly along the ridge, suggesting potential for faster and cooler data transfer in devices