Mechanisms for the emission of visible light from GaAs field-effect transistors

The emission of visible light from GaAs metal-semiconductor field-effect transistors under high electric field conditions is studied in detail in order to learn more about the luminescence mechanism. The electroluminescence spectrum is examined for energies both greater and less than the energy gap. It is seen that the form of the subgap spectrum can be explained by a Bremsstrahlung mechanism. However, the prominence of a voltage-dependent band-gap peak indicates that recombination processes also contribute to visible photon emission. A strongly polarized component of electroluminescence further substantiates the existence of radiative elastic collisions (Bremsstrahlung) and may provide insights into the scattering behavior of electrons in the channel.