Regensburg 2013 – wissenschaftliches Programm

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HL: Fachverband Halbleiterphysik

HL 70: Poster Session: Devices; Preparation and characterization; C/diamond; Si/Ge

HL 70.21: Poster

Mittwoch, 13. März 2013, 16:00–20:00, Poster A

BCS-type condensate in the electron-hole plasma of silicon — •Dietrich Schneider, Dirk Semkat, and Heinrich Stolz — University of Rostock

Quantum condensation phenomena in highly excited semiconductors comprise, besides the Bose-Einstein condensate of excitons, also a BCS-type condensate of weakly correlated electron-hole pairs at very low temperatures and high densities, where excitons can no longer exist. The key quantity of the BCS condensate is the so-called gap function. We present theoretical results for this quantity based on a recent approach. The gap function modifies the single-particle spectrum of the carriers. These modifications are transformed in the usual way into alterations of the high-energy tail of the electron-hole pair luminescence spectrum. Therefore, the occurrence of BCS condensed electron-hole pairs, i.e., a nonzero gap function, should manifest itself in the luminescence spectrum. We present first experiments where the electron-hole plasma in silicon is captured in a stress-induced potential trap at temperatures below 100 mK. Results for the measured spectra are shown and compared to the theoretical predictions.