Terahertz emission from the structures containing low-temperature-grown GaAs layers

We investigate the performance of n-GaAs surface plasmon type emitters of terahertz radiation having surface layers grown by low-temperature molecular beam epitaxy technology. Emitters with Be-doped low-temperature-grown GaAs layers on the surface radiate transients that are up to five times more powerful than those obtained from reference devices without these layers. Moreover, terahertz output from the modified emitters shows much weaker saturation at large optical intensities. Differences in the shapes of terahertz transients generated by both types of devices are discussed in terms, of electron and hole dynamics inside the structures.