
544 Examples of Ultrafast Processes in Matter
11.4. ULTRAFAST PROCESSES IN
SOLID-STATE MATERIALS
11.4.1. Excitation Across the Band Gap
Femtosecond techniques made it possible to resolve fundamental interaction
mechanisms and times in solids at room temperature. These processes are of
tremendous importance. For instance, they determine physical limits for speed
and miniaturization in semiconductor devices. Figure 11.7 illustrates essential
processes in semiconductors, following optical excitation above the band gap.
For a comprehensive review of ultrafast processes in semiconductors probed by
laser pulses, see Shah [3].
An ultrashort light pulse of frequency ...