Возбуждение терагерцевого излучения в p-n-гетероструктурах на основе a-Si:H/c-Si

Abstract

The results of studying the generation of terahertz (THz) radiation in p-n-heterostructures based on a-Si:H//c-Si upon their photoexcitation by radiation from a femtosecond titanium-sapphire laser with a wavelength of 800 nm are presented. The properties of the observed THz radiation can be explained by excitation of fast photocurrent of nonequilibrium charge carriers created in the region of the potential barrier under femtosecond interband photoexcitation of the structure. The fast photocurrent, in turn, emits a THz electromagnetic wave. The waveforms and amplitude spectra of the observed THz radiation reflect the dynamics of photoexcited charge carriers in structures. In terms of intensity, the THz radiation observed from the studied p–n heterostructures based on a-Si:H//c-Si is comparable to the THz radiation generated in n-InAs crystals, which are widely used as emitters in systems of THz time-domain spectroscopy. Therefore, a-Si:H//c-Si p-n-heterostructures can be used as THz emitters for solving tasks of THz spectroscopy.