Raman spectroscopic assessment of laterally structured δ-doped GaAs: Si

• Published in: Surface science Vol. 267; no. 1; pp. 274 - 276
• Main Authors: Wagner, J., Hülsmann, A., Kaufel, G., Köhler, K.
• Format: Journal Article Conference Proceeding
• Language: English
• Published: Lausanne Elsevier B.V 1992; Amsterdam Elsevier Science; New York, NY
• Subjects: Condensed matter: electronic structure, electrical, magnetic, and optical properties; Exact sciences and technology; Optical properties and condensed-matter spectroscopy and other interactions of matter with particles and radiation; Optical properties of specific thin films; Physics
• ISSN: 0039-6028; 1879-2758
• DOI: 10.1016/0039-6028(92)91136-Y

Laterally structured Si δ-doped GaAs has been investigated by photoluminescence and Raman spectroscopy. Wires were fabricated by electron beam lithography followed by reactive ion mesa etching. Radiative recombination across the E 0 + Δ 0 band gap is observed down to the narrowest wire width of 150 nm indicating the presence of an electron gas even in those structures. Collective intersubband plasmon-phonon modes measured by inelastic light scattering exhibit a down-shift in energy which indicates a reduction of the free carrier concentration caused by electron traps in the sidewalls. Spin-density excitation energies, by contrast, which give essentially the energy spacings of the electron subbands formed in the quasi-two-dimensional electron gas associated with the δ-doping layer, show a slight shift to higher energies possibly due to a rearrangement of the electron subbands caused by the additional lateral confinement.