Abstract-Terahertz pulse emission from GaInAsBi

Journal of Applied Physics

V. Pačebutasa, S. Stanionytė,  R. Norkus,  A. Bičiūnas, A. Urbanowicz,  A. Krotkus

https://aip.scitation.org/doi/abs/10.1063/1.5089855

Quaternary GaInAsBi alloy epitaxial layers were grown on InP substrates with 6% Bi. It was found that the thick layers remain fully strained. The measured carrier lifetimes were of the order of a few picoseconds. The terahertz (THz) emission was investigated using a GaInAsBi layer as an unbiased surface emitter and as a substrate for photoconductive antenna. It was observed that fabricated THz emitters were sensitive to the optical pulses with wavelengths longer than 2 μm. The demonstrated spectral characteristics of THz pulses obtained when using an Er-doped fiber laser for photoexcitation were comparable with those observed in other emitters used for THz-time-domain spectroscopy systems.

Abstract-THz-excitation spectroscopy technique for band-offset determination

V. Karpus, R. Norkus, R. Butkutė, S. Stanionytė, B. Čechavičius, A. Krotkus

Fig. 3 Experimental setup for THz excitation spectroscopy measurements.

https://www.osapublishing.org/oe/abstract.cfm?uri=oe-26-26-33807

The experimental THz-excitation spectroscopy technique for determining heterojunction band offsets is suggested. When photoexcited electrons gain sufficient energy to pass the potential barrier corresponding to a conduction band offset, an amplitude of THz-emission pulse sharply increases, which allows for direct measurements of the offset value. The technique is applied for determining GaAsBi-GaAs band offsets. The deduced conduction band offset of GaAsBi-GaAs heterojunction has about 45% of an energy gap difference at the Bi concentrations x <0.12 investigated.

© 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement