Abstract |
This work reports on the development of the photomixing technology and its immediate application to realize a tunable coherent source in the terahertz (THz) frequency range with an unprecedented bandwidth. An extensive experimental study of low-temperature-grown gallium arsenide (LT- GaAs) and ion-implanted GaAs as photomixing materials is performed in order to determine the optimal material parameters and fabrication conditions.
Defect Engineering allows to create photoconducting materials with outstanding properties for THz signal generation. The type and concentration of semiconductor defects has a critical importance in the performance of the material used for photomixing. In LT-GaAs, defects are highly dependent on the arsenic beam equivalent pressure (BEP), growth and anneal temperature. Unfortunately, the growth temperature at which an LT- GaAs sample shows optimal properties lacks very often of fabrication reproducibility. In contrast to LT-GaAs, the defects created in ion-implanted GaAs can be tailored by varying the implantation dose and energy. In order to achieve a given concentration of defects, Monte Carlo simulations were performed to determine optimal implantation conditions. The precise control over implantation dose and energy allows to overcome the reproducibility limitations of LT-GaAs. more...
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