Terahertz spectra emitted from hot carriers in two-dimensional semiconductors

We propose a simple method to calculate the spectrum of spontaneous teraher tz (THz) emission from hot carriers in two-dimensional semiconductors by me ans, of transport quantities, which are easily obtained during the process of solving the transport problem using the recently developed balance-equat ion approach for THZ-driven transport. The method has been applied to exami ne. the surface emission from a GaAs/AlGaAs heterojunction and the edge emi ssion from a GaAs based multiple quantum-well system subjected to strong dc biases. The theoretical results obtained are in reasonably good agreement with measurements.