Direct and simultaneous observation of ultrafast electron and hole dynamics in germanium.

ABSTRACT: Understanding excited carrier dynamics in semiconductors is crucial for the development of photovoltaics and efficient photonic devices. However, overlapping spectral features in optical pump-probe spectroscopy often render assignments of separate electron and hole carrier dynamics ambiguous. Here, ultrafast electron and hole dynamics in germanium nanocrystalline thin films are directly and simultaneously observed by ultrafast transient absorption spectroscopy in the extreme ultraviolet at the germanium M_4,5 edge. We decompose the spectra into contributions of electronic state blocking and photo-induced band shifts at a carrier density of 8 × 10²⁰ cm^-3. Separate electron and hole relaxation times are observed as a function of hot carrier energies. A first-o

SUBMITTER: Zurch M 

PROVIDER: S-EPMC5461502 | biostudies-literature | 2017 Jun

REPOSITORIES: biostudies-literature