10.3 Exciton Recombination
313
Fig. 10.9 a Low-temperature photoluminescence spectrum of ZnO implanted with 111 In featuring the so-called I 9 -line.
Spectra are recorded at various times after implantation as labeled. b Intensity of I 9 -line as a function of time. Adapted
from [967]
(a)
1.510
1.515
1
20
4
40
exc.
TES
(D ,X)
0
(b)
E C
n=1
E D
E V
n=2
n=3
D
0
X
D
0
*
Fig. 10.10 a Photoluminescence spectrum (T = 1.5 K, D = 50 mW cm −2 ) of high-purity GaAs with two donors (Ge
and Se/Sn). The lower spectrum has been excited 6 meV above the band gap, the upper spectrum has been resonantly
excited with the laser set to the (D 0 ,X) transition and exhibits n = 2, 3, 4, and 5 TES transitions. α,β,γ denote excited
(hole rotational) states of the (D 0 ,X) complex. Adapted from [969]. b Schematic representation of the n = 2 TES process,
left: initial, right: final state
(D
0 ,X) transition in enriched Si is found to be much sharper (< 40 µeV) than in natural Si (330 µeV)
[970]. At higher resolution, a hyperfine splitting of 485 neV due to the
31 P nuclear spin I = 1/2
(2 × 10
12 cm
−3 ) in isotopically pure (99.991%)
28 Si (I = 0) is observed for the (P
0 ,X) recombination
[973]. In a magnetic field, the Zeeman-split lines have a FWHM of about 150 neV.
In Fig. 10.12 the recombination of excitons bound to the N isoelectronic impurity in lowly doped
GaP is shown. The efficient recombination of nitrogen-bound electrons with holes at the point is
due to the wave-function component of the localized electron at k = 0 [690] (Fig. 7.40). The decay
time of the A exciton is about 40 ns [974] and thus larger than the typical lifetime of excitons in direct
semiconductors (ns-range). The forbidden B exciton has a much longer lifetime of 4 µs [974].
In the case of In in GaAs it has been found that down to the regime of N In < 10
19 cm
−3 the indium
does not act as a substitutional isoelectronic impurity but still fully participates in the composition
313
Fig. 10.9 a Low-temperature photoluminescence spectrum of ZnO implanted with 111 In featuring the so-called I 9 -line.
Spectra are recorded at various times after implantation as labeled. b Intensity of I 9 -line as a function of time. Adapted
from [967]
(a)
1.510
1.515
1
20
4
40
exc.
TES
(D ,X)
0
(b)
E C
n=1
E D
E V
n=2
n=3
D
0
X
D
0
*
Fig. 10.10 a Photoluminescence spectrum (T = 1.5 K, D = 50 mW cm −2 ) of high-purity GaAs with two donors (Ge
and Se/Sn). The lower spectrum has been excited 6 meV above the band gap, the upper spectrum has been resonantly
excited with the laser set to the (D 0 ,X) transition and exhibits n = 2, 3, 4, and 5 TES transitions. α,β,γ denote excited
(hole rotational) states of the (D 0 ,X) complex. Adapted from [969]. b Schematic representation of the n = 2 TES process,
left: initial, right: final state
(D
0 ,X) transition in enriched Si is found to be much sharper (< 40 µeV) than in natural Si (330 µeV)
[970]. At higher resolution, a hyperfine splitting of 485 neV due to the
31 P nuclear spin I = 1/2
(2 × 10
12 cm
−3 ) in isotopically pure (99.991%)
28 Si (I = 0) is observed for the (P
0 ,X) recombination
[973]. In a magnetic field, the Zeeman-split lines have a FWHM of about 150 neV.
In Fig. 10.12 the recombination of excitons bound to the N isoelectronic impurity in lowly doped
GaP is shown. The efficient recombination of nitrogen-bound electrons with holes at the point is
due to the wave-function component of the localized electron at k = 0 [690] (Fig. 7.40). The decay
time of the A exciton is about 40 ns [974] and thus larger than the typical lifetime of excitons in direct
semiconductors (ns-range). The forbidden B exciton has a much longer lifetime of 4 µs [974].
In the case of In in GaAs it has been found that down to the regime of N In < 10
19 cm
−3 the indium
does not act as a substitutional isoelectronic impurity but still fully participates in the composition