Temperature-dependent terahertz time-domain spectroscopy of 3D, 2D, and 0D semiconductor heterostructures

Carrier transport in semiconductors with different dimensionalities, i.e., 3D (bulk), 2D (QW), and 0D (QD), were investigated via temperature-dependent terahertz time-domain spectroscopy (THz-TDS). The optical properties and recombination dynamics in the samples were probed via photoluminescence spectroscopy. The temperature-dependence of the THz emission from the samples was explained in the context of the drift-diffusion model using the dominant THz radiation mechanism. The THz emission from diffusion-type THz emitters such as p- and n-InAs decreases as temperature increases due to mobility decrease. Conversely, the THz emission from drift-type THz emitters such as SI-GaAs, GaAs QW, and InAs QD was found to increase with temperature due to the increase in the driving electric field. In summary, THz-TDS can be utilized to gain qualitative insights on the temperature-dependent transport characteristics and establish dominant THz radiation mechanisms.