314
10 Recombination
Si:Al
28
Si
1.1508
1.1509
1.1510
natural
Si
A 0
A
0 X
Fig. 10.11 High-resolution photoluminescence (PL) spectra of (A 0 ,X) recombination in natural and 28 Si-enriched
silicon doped with aluminum (T = 1.8 K). The 28 Si PL spectrum is shifted up in energy by 0.114 meV, as indicated
by the arrow, to compensate for the shift in band gap. The inset shows a level scheme for the recombination in natural
silicon. Adapted from [971], reprinted with permission, ©(2002) APS
Fig. 10.12 Photoluminescence
spectrum (T = 4.2 K) of
GaP:N
(N N ≈ 5 × 10 16 cm −3 ).
The A exciton is bound to
an isolated nitrogen
impurity, cmp. to Fig. 9.28.
Adapted from [690]
Fig. 10.13 Spectral
position of neutral donorand acceptor-bound exciton
photoluminescence
transition (T = 2 K) in
GaAs doped with different
amounts of indium relative
to the donor-bound exciton
luminescence in pure GaAs
(1.5146 eV). Adapted
from [975]
of a pseudo-binary system (Sect. 6.5). Recombination from excitons bound to single indium atoms or
In–In pairs could not be found. The energy shift of donor- and acceptor-bound excitons in the dilute
limit (Fig. 10.13) follows the band-gap dependence established for larger indium concentrations. The
non-occurrence of localization effects is attributed to the small effective electron mass in InAs [544].