Magnetic-field enhancement of terahertz emission from semiconductor surfaces: A comparison of experiment with a semiclassical model

摘要

The possibility of strong enhancement of terahertz (THz) emission from photogenerated carriers in the surface depletion region of a semiconductor under the influence of external magnetic fields has been well documented in the literature. We describe a simple theory to explain the key features of this phenomenon. The model is based on a combination of the Drude-Lorentz approximation for the carrier dynamics with an appropriate solution of the radiation problem. The magnetic-field enhancement of THz emission arises primarily from the increased radiation efficiency of transient currents flowing in the plane of the surface. The model provides quantitative agreement with experiment for the pronounced angular dependence of the enhancement and predicts the correct trend for degree of enhancement in a variety of semiconductors.