Ultrafast terahertz emission properties in GaAs semiconductor

Aihua Wang; Yulei Shi; Qingli Zhou

doi:10.1117/12.2196272

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12 August 2015 Ultrafast terahertz emission properties in GaAs semiconductor

Aihua Wang, Yulei Shi, Qingli Zhou

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Proceedings Volume 9625, 2015 International Conference on Optical Instruments and Technology: Terahertz Technologies and Applications; 962505 (2015) https://doi.org/10.1117/12.2196272
Event: International Conference on Optical Instruments and Technology 2015, 2015, Beijing, China

Abstract

Ultrafast carrier dynamics in Schottky barriers is an extremely active area of research in recent years. The observation of the generation of terahertz pulses from metal/semiconductor interfaces provides a technique to characterize electronic properties of these materials. However, a detailed analysis of these phenomena has not been performed satisfactorily. In this work, the measurements of optically generated terahertz emission from Au/GaAs interfaces are investigated in detail. We observe that, under high laser power excitation, terahertz signals from bare GaAs wafers and Au/GaAs samples exhibit an opposite polarity. The polarity-flip behaviors in the terahertz beams are also observed in the temperature-dependent measurements and the femtosecond pump-generation studies of the Au/GaAs interfaces. These effects can be fully explained in terms of the dynamics of carrier transfer in the Au/GaAs Schottky barriers, which involves the internal photoelectric emission and the electron tunneling effect, and picosecond time constants are found for these processes.

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Aihua Wang, Yulei Shi, and Qingli Zhou " Ultrafast terahertz emission properties in GaAs semiconductor", Proc. SPIE 9625, 2015 International Conference on Optical Instruments and Technology: Terahertz Technologies and Applications, 962505 (12 August 2015); https://doi.org/10.1117/12.2196272

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