Efficient Terahertz Generation Within InGaN/GaN Multiple Quantum Wells

Generation of Terahertz Radiation in LED Heterostructures with Multiple InGaN/GaN Quantum Wells at Two-Photon Excitation by Femtosecond

“…In contrast to the results [2][3][4], a decrease of the signal with increasing power density of the exciting pulse is observed rather, than the saturation. In [2][3][4], the saturation is explained by the complete screening of the built-in piezoelectric fields at certain pump power density levels and by the disappearance of the field separating the carriers in the quantum well. A decrease in the amplitude of the terahertz signal with increasing pump power density can be due, Fig.…”

“…When comparing our experimental results with those obtained previously, it should be taken into account that in [2][3][4][5], the laser radiation at a wavelength of 400 nm was used to excite the generation (the photon energy is sufficient for the interband transitions in quantum wells). This radiation resulted from the generation of the second harmonic of radiation of the Ti:sapphire laser in the BBO crystal.…”

“…Mechanisms of generation of terahertz pulses from the surfaces of bulk semiconductors are established and well described by the existing models. In heterostructures, the mechanisms may be more complicated [1][2][3][4][5] and are of great interest, since they are connected with the fundamental properties of structures, many of which can be calculated with the use of modern quantum mechanical methods. In [2,3], as the main cause for the generation of electromagnetic radiation in the terahertz frequency range under excitation of InGaN/GaN heterostructures by optical pulses of femtosecond duration, the dynamic screening of the build-in piezoelectric fields by the photoexcited charge carriers is proposed.…”

“…According to [4], in InGaN/GaN heterostructures, the strong built-in fields and high concentration of charge carriers in quantum wells can lead to the more efficient generation of terahertz radiation in comparison with the generation from the surface of bulk semiconductors. In the literature, there is no unambiguous opinion on the critical value of the dynamic screening of piezoelectric fields [5].…”

“…The parameters and excitation conditions differ from those described in [2][3][4][5]. The structures under study are promising materials in modern optoelectronics that allow to create high-power LEDs with a wide range of applications.…”