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9 September 1999 Free-electron laser studies of intra-acceptor transitions in GaAs: a potential far-infrared emission system
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Proceedings Volume 3828, Terahertz Spectroscopy and Applications II; (1999)
Event: Industrial Lasers and Inspection (EUROPTO Series), 1999, Munich, Germany
Normal dopant species in III-V semiconductors from shallow donors or acceptors whose atomic-like transitions have energies of the order of 3-20meV which corresponds to the Terahertz region of the spectrum. It has been suggested that these levels could be utilized in an impurity based THz laser system developing a solid-state THz source from such a technology will require engineering of the energy levels to favor radiative recombination. In this paper we report initial experiments to measure the 1s-2p scattering rate for holes bound to Beryllium acceptors in a bulk GaAs epilayer using the European free electron laser facility FELIX. Two absorption lines were studied the so-called D and C lines at 167 cm-1 corresponding to 1s-2p transitions of the Beryllium acceptors. At high pump powers these lines were saturated and it was possible to perform Pump-probe measurements to observe the recovery of the absorption as a function of time. The temperature dependence of the decays was also measured. The D and C transitions were found to decay with lifetimes of 360ps and 440ps respectively. This represents the firs direct measurement of these transition lifetimes which are much longer than those reported for intersubband scattering. The result are highly encouraging and support the concept of an impurity based Terahertz device for room temperature operation.
© (1999) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.
Matthew P. Halsall, Paul Harrison, H. Pellemans, and Carl R. Pidgeon "Free-electron laser studies of intra-acceptor transitions in GaAs: a potential far-infrared emission system", Proc. SPIE 3828, Terahertz Spectroscopy and Applications II, (9 September 1999);

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