Аннотация:The influence of the built-in electric field in heterostructures on the generation of terahertz (THz) radiation under femtosecond laser pumping of the heterostructure surfaces has been investigated. The heterostructures consist of elastically strained superlattices of In0.53+Δ xGa0.47-Δ xAs/In0.52-Δ xAl0.48+Δ xAs, epitaxially grown on InP substrates with (100) and (111)A orientations. The value of Δ x, and hence the value of strain, varied in series of samples. The "red" shift of the peak in the photoluminescence spectra confirms the presence of an integrated electric field in (111)A-heterostructures caused by the piezoelectric effect. It is shown that (100)-heterostructures generate a THz signal of approximately the same level (the scatter of THz field amplitude values is no more than 30% of the average value) regardless of strain, while in a series of (111)A-heterostructures the THz signal significantly increases (by 75-90%) for highly strained samples. Keywords: molecular beam epitaxy, GaAs, InGaAs, piezoelectric effect, terahertz emission, femtosecond laser.
