Detection of single photons using a field effect transistor with a layer of quantum dots

We demonstrate single-photon detection with a GaAs/AlGaAs modulation-doped field effect transistor. High sensitivity of the transistor to light is obtained by incorporating in its structure a layer of self-organized InAs quantum dots in close proximity to the conducting channel but separated by a thin AlGaAs barrier. We show that capture of a single photoexcited carrier by a quantum dot results in a sizeable change in the source–drain current of the transistor, allowing the detection of a single photon.