Semiconductor LT-GaAs material successfully applied to prepare terahertz antenna

September 08, 2023

Terahertz (THz) waves generally refer to electromagnetic waves having a frequency of 0.1 to 10 THz (a wavelength in the range of 0.03 to 3 mm between microwave and infrared waves). Terahertz imaging and spectroscopy will be the main technologies for terahertz applications. Terahertz has high frequency and ultra-short pulse (picosecond) characteristics, giving it high spatial resolution and temporal resolution. Terahertz energy is small and does not damage the material, so it has advantages over X-ray technology. In addition, the vibrational and rotational resonance frequencies of many biological macromolecules are also in the terahertz band. Therefore, the development of terahertz wave technology will be applied in various fields such as broadband communications, radar detection, electronic countermeasures, electromagnetic weapons, astronomy, markerless gene inspection, cell imaging, non-destructive testing, biochemical examination, grain selection, and species selection. Development has far-reaching implications.

In recent years, the research group of new semiconductor optoelectronic materials and quantum devices of the Institute of Semiconductors, Chinese Academy of Sciences conducted research on terahertz transceivers and materials in the time domain, mainly semiconductor ultrashort pulse lasers and ultrashort carriers. GaAs transceiving antenna device. After years of long-term accumulation, the research group has developed ultrashort-lived carriers and high-resistance (greater than 1E8 ohm.cm) low-temperature LT-GaAs materials.

On this basis, a terahertz LT-GaAs broadband THz photoconductive antenna was developed in cooperation with the Institute of Electronic Engineering of the Chinese Academy of Engineering Physics. The antenna was excited at a frequency of 75 kHz and a pulse width of 100 fs to obtain a THz wave with a spectral width of 0.1-2.7 THz. The LT-GaAs-based terahertz antenna has a nearly two-times increase in terahertz spectral bandwidth under the same excitation conditions compared to a conventional semi-insulating SI-GaAs material. The epitaxial LT-GaAs has an ultrashort carrier lifetime that makes it an ideal material system for fabricating THz photoconductive antennas.

Compared with the infrared wave device technology that has been widely used at present, the performance of the terahertz wave photoelectric device has yet to be fully optimized and improved. It is believed that with the rapid development of broadband high-stability pulsed terahertz sources, it will effectively promote the application of terahertz technology.

LT-GaAs THz Photo Conductor Antenna