6.8 Diamond Structured Si and Pb
125
Table 6.7 Binding energy information of the bcc(110) skins of Li, Na, and K [83–85]
Li [86]
Na [87]
K [88]
m = 1
i
z
E 1s (z)
E 2p (z)
E 3p (z)
bcc(110)
Atom
0
50.673
28.194
15.595
B
12
54.906
30.595
18.354
S 2
5.83
55.205
30.764
18.551
S 1
3.95
55.520
30.943
18.757
E 1s (12)
–
4.233
2.401
2.758
BOLS
14.8
15.0
15.2
15.4
Rb (110) 4p
45 eV
65 eV
45 - 65
(a)
Rb(110) 4p
hν = 65 eV
BE(eV)
Intensity(a.u.)
Exp
B
S 2
S 1
14.8
15.0
15.2
15.4
11.6 11.8 12.0 12.2 12.4
BOLS
(b)
Cs(110) 5p
hν = 21.2 eV
BE(eV)
Intensity(a.u.)
Exp
B
S 2
S 1
Fig. 6.20 BOLS − TB decomposition of the XPS 4p spectrum for a Rb(110) skin collected at
65 eV beam energy [86] and the 5p spectrum for b Cs(110) skin collected at 21.2 eV beam energy
[95] with the bulk B, S 2 , and S 1 components. The inset (a) shows the ZPS (difference between
spectra collected using 45 and 65 eV beam energies) distills the bulk valley (B = 14.940 eV) and
the monolayer skin component (S 1 = 15.127 eV). Reprinted with permission from [136]
6.8 Diamond Structured Si and Pb
6.8.1 Entrapment of the 2p and the Valence Band of Si
The valence band of the Si
+
N clusters [96] and Si(210) edge atoms show the quantum entrapment dominance. Figure 6.22a, b plot the size-resolved 2p and valence
band entrapment of Si
+
N (N = 5–92) obtained by Vodel et al. [96] using soft X-ray
photoionization method. Figure 6.22c is the size dependent 2p for porous Si with
effective clusters sizes of 1.4–2.1 nm [97]. Results show consistently that molecular undercoordination induces local quantum entrapment, agreeing the skin-XPS
derivatives (Sect. 4.5).
The entrapment of both the 2p and the valence bands follows the same N
−1/3
fashion. The cluster size N = 4πK
3 /3 is converted to K
−1
= (3N/4π)
−1/3
= 1.61N
−1/3 .
With respect to the known bulk E 2p (12) value at –99.2 eV, a 0.14 eV(= 99.2 − 99.06)
and a −3.4 (=99.2 − 102.6) eV offset correction is necessary, which arises from the
125
Table 6.7 Binding energy information of the bcc(110) skins of Li, Na, and K [83–85]
Li [86]
Na [87]
K [88]
m = 1
i
z
E 1s (z)
E 2p (z)
E 3p (z)
bcc(110)
Atom
0
50.673
28.194
15.595
B
12
54.906
30.595
18.354
S 2
5.83
55.205
30.764
18.551
S 1
3.95
55.520
30.943
18.757
E 1s (12)
–
4.233
2.401
2.758
BOLS
14.8
15.0
15.2
15.4
Rb (110) 4p
45 eV
65 eV
45 - 65
(a)
Rb(110) 4p
hν = 65 eV
BE(eV)
Intensity(a.u.)
Exp
B
S 2
S 1
14.8
15.0
15.2
15.4
11.6 11.8 12.0 12.2 12.4
BOLS
(b)
Cs(110) 5p
hν = 21.2 eV
BE(eV)
Intensity(a.u.)
Exp
B
S 2
S 1
Fig. 6.20 BOLS − TB decomposition of the XPS 4p spectrum for a Rb(110) skin collected at
65 eV beam energy [86] and the 5p spectrum for b Cs(110) skin collected at 21.2 eV beam energy
[95] with the bulk B, S 2 , and S 1 components. The inset (a) shows the ZPS (difference between
spectra collected using 45 and 65 eV beam energies) distills the bulk valley (B = 14.940 eV) and
the monolayer skin component (S 1 = 15.127 eV). Reprinted with permission from [136]
6.8 Diamond Structured Si and Pb
6.8.1 Entrapment of the 2p and the Valence Band of Si
The valence band of the Si
+
N clusters [96] and Si(210) edge atoms show the quantum entrapment dominance. Figure 6.22a, b plot the size-resolved 2p and valence
band entrapment of Si
+
N (N = 5–92) obtained by Vodel et al. [96] using soft X-ray
photoionization method. Figure 6.22c is the size dependent 2p for porous Si with
effective clusters sizes of 1.4–2.1 nm [97]. Results show consistently that molecular undercoordination induces local quantum entrapment, agreeing the skin-XPS
derivatives (Sect. 4.5).
The entrapment of both the 2p and the valence bands follows the same N
−1/3
fashion. The cluster size N = 4πK
3 /3 is converted to K
−1
= (3N/4π)
−1/3
= 1.61N
−1/3 .
With respect to the known bulk E 2p (12) value at –99.2 eV, a 0.14 eV(= 99.2 − 99.06)
and a −3.4 (=99.2 − 102.6) eV offset correction is necessary, which arises from the