Electrical and Thermal Properties of Photoconductive Antennas Based on [In.sub.x][Ga.sub.1-x]As with a Metamorphic Buffer Layer for the Generation of Terahertz Radiation

The results of studies of the electrical and thermal properties of photoconductive antennas for terahertz-radiation generation are reported; these antennas are fabricated on the basis of low-temperature-grown GaAs (LT-GaAs) and [In.sub.x][Ga.sub.1-x]As with an increased content of indium (x > 0.3). It is shown that the power of Joule heating [P.sub.H] due to the effect of "dark" current in [In.sub.x][Ga.sub.1-x]As exceeds the same quantity in LT-GaAs by three-five times. This is due to the high intrinsic conductivity of [In.sub.x][Ga.sub.1-x]As at x > 0.38. Heat-removal equipment for the photoconductive antenna has been developed and fabricated. The results of numerical simulation show that the use of a heat sink makes it possible to reduce the operating temperature of the antenna based on LT-GaAs by 16%, of the antenna based on [In.sub.0.38][Ga.sub.0.62] As by 40%, and for antennas based on [In.sub.0.53][Ga.sub.0.47] As by 64%.