Hamburg 2001 – scientific programme

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HL: Halbleiterphysik

HL 24: Poster II

HL 24.2: Poster

Thursday, March 29, 2001, 10:30–19:00, Rang S\ 3

High-resolution cathodoluminescence study of free excitons in diamond — •N. Teofilov¹, R. Sauer¹, K. Thonke¹, H. Kanda², and T. Anthony³ — ¹Abteilung Halbleiterphysik, Universität Ulm, 89069 Ulm — ²NIRIM, Tsukuba, Ibraki 305, Japan — ³General Electric Corporate Research and Development, Schenectady, New York 12309, USA

Recent cathodoluminescence (CL) work on low-strain, high purity HPHT diamonds has demonstrated that the recombination spectrum of free excitons is much more complex than reported previously. The origin of the spectral structure is still being disputed including spin-orbit and spin-spin splitting effects. In the present study we continue these high resolution CL measurements with special emphasis on the temperature dependence of the exciton fine structure. While most of the fine structure components can be resolved in all optically active wave vector-conserving phonon replicas (TA, TO, and LO), their relative coupling strength are extremely different. We have taken spectra at controlled temperatures from 8K to 90K. The spectra are deconvoluted for their temperature dependence to yield a complete level scheme in pursue of the interpretation of the excitonic fine structure.