Optical spectroscopy on a series of n-type modulation-doped Ga0.47In0.53As/Al0.48In0.52As single quantum wells reveals that the Fermi-edge singularity in luminescence occurs only if localization of photogenerated holes leads to positively charged centers. If the hole localization yields electrically neutral centers, no intensity enhancement of the luminescence near the Fermi edge is observed. The different nature of the hole-localization mechanisms consistently explains previous discrepancies in both the low-temperature luminescence and absorption spectra of the two-dimensional electron gas in Si metal-oxide-semiconductors field-effects transistors as well as in modulation-doped GaAs/AlxGa1-xAs, GaxIn1-xAs/InP, and GaxIn1-xAs/AlyIn-yAs quantum wells and heterostructures.
ASJC Scopus subject areas
- Condensed Matter Physics