Photoconductivity of Be-doped GaAs under intense terahertz radiation

• Published in: Solid state communications 2002-04, Vol.122 (3), p.223-228
• Main Authors: Lewis, R.A., Bradley, I.V., Henini, M.
• Format: Article
• Language: English
• Subjects: A. Semiconductors; C. Impurities in semiconductors; Condensed matter: electronic structure, electrical, magnetic, and optical properties; D. Electronic states (localized); E. Light absorption and reflection; Electron states; Exact sciences and technology; Iii-v and ii-vi semiconductors; Iii-v semiconductors; Impurity and defect levels; Infrared and raman spectra and scattering; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Physics
• ISSN: 0038-1098; 1879-2766
• DOI: 10.1016/S0038-1098(02)00084-4

Lyman transitions of the Be acceptor in GaAs have been investigated under intense radiation generated by a free electron laser. Photoconductivity was found to be a more sensitive method than transmission for detecting the transitions. Three regimes of photoconductive response were distinguished: at high intensity, the signal saturates; at intermediate intensity, it is proportional to intensity; at low intensity, it is background limited. Spectra were obtained by wavelength scanning and showed excellent reproducibility from run to run. With increasing radiation intensity, the D and C lines, being transitions from the 1s 3/2(Γ 8 +) ground state to the 2p 5/2(Γ 8 −) and 2p 5/2(Γ 7 −) excited states, respectively, exhibit a pronounced splitting and broadening of components. This behavior is attributed to thermal stress induced by localized heating.