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Chanter 10
Cubic Cadmium Sulphide
(c-CdS)
10.1 STRUCTURA L PROPERTIES
10.1.1 Ionicity
Table 10.1.1 Phillips's ionicityAfor c-CdS [ I ,11.
f;
0.685[1.11 J. C. Phillips, Bonds and Bands in Semiconductors (Academic, New York, 1973).
10.1.2 Elemental Isotopic Abundance and Molecular Weight
Isotopic abundance
Table 10.1.2 Isotopic abundance in percentfor cadmium and sulfirr [1,2].
Isotope YO at. abundance Isotope % nat. abundance Isotope % nat. abundance
Io6Cd I .25 I2Cd 24.13 32s 95.02
"'Cd 0.89 'I3Cd 12.22 33s 0.75"'Cd 12.49 'I4Cd 28.73 34s 4.2 1
'"Cd 12.80 Ii6Cd 7.49 36s 0.02
[1.2] D. R. Lide, CRC Handbook of Chemistry and Physics, 78th Edition (CRC Press, Boca Raton,1997).
255
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256 Cubic Cadmium Sulphide (cCdS)
0 M olecular weight
Table 10.1.3 Molecular (average atomic) weight Mfor e-CdS.
M (amu)
144.477
10.1.3 Crystal Structure and Space Group
Table 10.1.4 Crystal structure and its space and pint groupsfor e-CdS.
Crystal structure Space g o u p Point group
Zincblende (Cubic) F 4 3 m T d
10.1.4 Lattice Constant and Its Related Parameters0 Lattice constant, near-neighbor distance, etc.
Table 10.1.5 Lattice constant (a), near-neighbor distance (4, unit cube volume (a3), andmolecular density (dn)for e-CdS at 300 K.
Parameter Value
Lattice constant a (A)
d (Cation-Anion) (A)
d (Cation-Cation) (A)
Unit cube volume a3 (10-22m3)
5.825 [1.3]
2.522"
4.119"
1.976"
Molecular density dM (1022 m - ~ ) 2.024"
[1.31W. R. Cook, Jr., J . Am. Cerum.Soc. 51,5 18 (1 968).
*Calculated.
0 Crystal density
Table 10.1.6 Crystal density gfor e-CdS at 300K. *
g (gicm3)
4.855
*Calculatedusing ~ 5 . 8 2 5 .
10.1.5 Structural Phase Transition
Table 10.1.7 Structural phase transition in e-CdS at high temperatures.~~
Structure Transition temperature ("C)
Zincblende (F 4 3 m ) Room temperatureWurtzite (P63mc) 300 [1.41
[1.410.Zelaya-Angel and R. Lozada-Morales, Phys. Rev. B 62,13064 (2000).
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10.2 Thermal Propert ies
p 1475'C -/
/
1400-
257
- -
10.1.6 Cleavage Plane
Table 10.1.8 Cystallogra phic plane most readily cleaved o r e-CdS.*
Cleavage plane
(110)
*Expected.
I600
/
-
-
800
ooo-
400 -Cd 0
200 -
-
-
-
-cdS
Surface energy
Table 10.1.9 Surface enevgyfor e-CdS (in J/m2).
-tI
-
- -
- -I7'
213' ,,Se
d
-(6 CdSe
Plane
1.06 1.07 0.69 Calc. r1.51
11.51 B N:Oshcherin, Phys. Status Solidi A 34, K18 1 (1976).
I0.2 THERM AL PROPERTIESI10.2.1 Melting Point and Its Related Parameters
Table 10.2.1 Melting poin t T,,, and its related parameter f o r CdS.
Parameter Value
Melting point T,,, (K) 1748 [2.1]
Entropy of fusion AS, (cal/mol K) 16.21 [2.2]
[2. ] H. H. Woodbury, J. Phys. Chem. Solids 2 4 , 8 81 (1963).[2.2] See, B. R. Nag, J. Electron. Matel: 26, 70 (1997).
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258 Cubic Cadmium Sulphide (c C d S )
10.2.2 Specific Heat
No detailed data are available for c-CdS .
10.2.3 Debye Temperature
No detailed data are available for c-CdS.
10.2.4 Thermal Expansion Coefficient
No detailed data are available for c-CdS.
10.2.5 Therm al Conductivity and Diffusivity
No detailed data are available for c-CdS .
10.3 ELA STIC PROPERTIES
10.3.1 Elastic Constant0 Room-temperature value
Table 10.3.1 Elastic stifiess a n d compliance constantsfo r c-CdSa t 300K.
Parameter Value
Stiffness (10" dyn/cm2) [3.1]
CI 1 7.70CI 2 5.39c44 2.36
SI 1 3.07
S44 4.24
[3. ] Average values [see,Data andFunctiona1 Relationships in Science and Technology,edited by K.-H.Hellwege and A. M. Hellwege, Landolt-Bornstein, New Series, Group 111 Vol. 11 (Springer, Ber-lin, 1979)l.
[3.2] Calculated from C, values.
Compliance (lo-'*cm2/dyn) [3.2]
SI2 -1.26
10.3.2 Third-Order Elastic Constant
Table 10.3.2 Third-order elastic constant of c-CdS [3.3].
Modulus Value (10' dyn/cm2)
Clll -2.5
CI 12 -2.8c123 -1.9
c144 +0.3
c456 +0.4
c166 -0.6
[ 3 . 3 ]Numerical Data and Functional Relationships in Science and Technology, edited by K.-H. Hell-wege and A . M. Hellwege, Landolt-Bornstein, New Series, Group 111 Vol. 11 (Springer, Berlin,1979).
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10.3 Elast ic Properties 259
10.3.3 Young’s M odulus, Poisson’s Ratio, and Similar0 Young’s modulus
Table 10.3.3 YoungS modulus Y fo r c-CdS at 300K. *
Crystallographic plane Y (10” dyn/cm2)( 100)plane
[ O O l ] direction 3.26[Ol l ]direction 5.09
[ O O l ] direction 3.261111 direction 6.26
(110) plane
( 1 1 1 ) plane 5.09
*Calculated using Sll= 3.07,S 12 =-l 26, and S ~ 4 . 2 4all in cm’idyn).
0 Poisson’s ratio
Table 10.3.4 Poisson . ratio P fo r c-CdS at 300 K. *
Crystallographic plane P
( 100)planem=[010], =[001] 0.4 10
m=[011], =[ 0i1] 0.079
m=[001], =[li01 0.410(1 10)plane
( 1 11 ) plane 0.454
*Calculated using Sll=3 .07,SI2=1.26, and S4=4.24 (all in cm2/dyn).
0 Bulk modulus, shear modulus, etc.
Table 10.3.5 Bulk modulus, B , ,pressure derivative of B, , dB, /dp, shear modulus, C,, isotropy
factor;A, linear com pressibility,C,,, Caucy ratio, C,, and Born ratio, B o ,for c-CdS at 300K ,Parameter Value
~~ ~
B, (10’ dyn/cm2) 6.16 [3.4]
dB, ldp 4.8 [3.5]
C, (10’ d y d c m 2 ) 1.16 [3.4]
A 0.489 [3.4]
C , (1O-I3 cm21dyn) 5.41 [3.4]
ca 2.28 [3.4]
Bo 1.04 [3.4 ]
[3.4] Calculated using Cll= 7.70,C12=5.39, and C ~ = 2 . 3 6all in 10” dyn/cm2).[3.5] Theor. [S.-H. Wei and A . Zunger, Phys. Rev. B 60,5404 (1999)l.
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260 Cubic Cadmium Sulphide (cCdS)
10.3.4 Microhardness
No detailed data are available for c-CdS .
10.3.5 Sound VelocityTable 10.3.6 Sound velocitypropagating in c-CdS at 300 K. * LA=longitudinal acoustic; TAl,TAZ=transverse acoustic.
Propagation direction Mode Sound velocity (1Os c d s )
3.98
2.20
4.28
1.54
2.204.38
[ 1 1 1 1 TAl,TA2 1.79
*Calculated using Cl =7.70x10" dyn/cm2, CI2=5.39x 0" dyn/cm2, C 4=2.36x 10" dyn/crn2, andg4.855 g/cm3.
I0.4 PHONO NS AND LATTICE VIBRON ICI PROPERTIES
10.4.1 Phonon D ispersion Relation
Lattice dynamics and phonon dispersion curves for c-CdS has been discussed theoretically byM . A.Nusimovici and J. L.Birman [Phys.Rev. 156,925 1 967)].
10.4.2 Phonon Frequency0 Room-temperature value
Table 10.4.1 Long-wavelength (q4)n d zone-boundary phonon fiequencies for c-CdS. *
Critical point Phonon Phonon frequency (cm -')
r TO 237
L O 303
X TALA
TO
LO
L TA 41
LA
TO 255
LO
*Estimated from w-CdS data.
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10.6 Energy-Band Structure: Energy-Band Gaps 261
10.4.3 Mode Gruneisen Parameter
No detailed data are av ailable for e-CdS.
10.4.4 Phonon Deformation PotentialNo detailed data are available for c-CdS.
10.5 COLLECTIVE EFFEC TS AND RELATEDPROPERTIES
10.5.1 Piezoelectric Constant
No detailed data are available for e-CdS.
10.5.2 Frohlich Coup ling Constant
No detailed data are available for e-CdS.
10.6 ENERGY-BAND STRUCTURE: ENERGY-BAND
GAPS
10.6.1 Basic Properties0 Electronic energy-band structure
Fig. 10.6.1 Electronic energy-band structure of c-CdSas calculated within the local-density-functional for-malism. [From A. Zunger and A. J. Freeman, Phys.Rev. B 17 , 4850 (1978).] The locations of several in-terband transitions are included by the vertical arrows.
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262 Cubic Cadmium Sulphide ( c C d S )
0 Electronic density of states
-I5 -10 - 5 0 5
ENERGY ( e V )
Fig.10.6.2
Electronic density of states for c-CdS as calculated within the local-density-functional for-malism. [From A. Zunger and A. J. Freeman, Phys. Rev. B 17,4 850 (1978).]
Energy eigenvalue
Table 10.6.1 Energy eigenvalues at thetion bands of c-CdS [6, ] .
X and L points fo r the valence andfir st m onduc-
Value (eV)
Calc. ExDer.*ritical point Level
r r6"(r > -1 1.46
I-7" (TI57 0.00 -0.07
TSV 0.00
r7c (r15c) 7.61 7.4
rsc
r6c (rlc) 2.62 2.40-2.55
X x6" (XI") -11.42 -13.85
x6" (x3") -2.64 -3.7, -4.8
x6" (x5") -1.06 -1.54, -1.9x7"
x7c (X37 5.45
x6c (XI') 5.24
L Lgv (Ll") -1 1.43
L6" (L ") -2.75 -4 .18 , -4 .8
Lgv (L3") -0.4 1 -0.62, -0.8
L4,5"
L4,5'
Lgc 04') 4.04
L6c (L37 8.36
[6.1]A. Zunger and A. J. Feeman, Phys. Rm. B 17,4 850 (1978).*The data are gathered from various sources.
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10.6 Energy-Band Structure: Energy-Band Gaps 263
10.6.2 &-Gap RegionTemperature dependence
Table 10.6.2 Eo- and EOiAo-gap energiesfor c-CdS determined at various temperatures.
Temperature (K) EO W EO+& ( e v ) C o m m e n t4.2 2.48 Epilayer on (1 1O)InP [6.2]
300 2.50 * '2.55 *2
Epilayer on (1 11)GaAs [6.3]
2.4 1
2.40f0.01 Polycrystalline film [6.5]
2.45 Polycrystalline film [6.6]
2.42 Polycrystalline film [6.7]
2.46 (2.53) Mean value (T=300 K)
Epilayer on (1 10)InP [6.4]
[6.2] D. R. T. Zahn, G Kudlek, U. Rossow, A. H o fh a n n , I. Broser, and W. Richter, A h , Matex Opt.
[6.3] M. Cardona, M. Weinstein, and G A. Wolff, Phys. Rev. 140, A633 (1 965).[6.4] U. Rossow, T. Weminghaus, D. R. T. Zahn, W. Richter, and K. Hom, Thin Solid Films 233, 176
[6.5]0.Zelaya-Angel, J. J. Alvarado-Gil, R. Lozada-M orales, H. Vargas, and A. F. da Silva, Appl. Phys.
[6.6]0.Zelaya-Angel and R. Lozada-Morales, Phys. Rev. B 62, 13064 (2000).[6.7]0.Vigil, 0.Zelaya-Angel, and Y. Rodriguez, Semicond. Sci.Technol. 15,2 59 (2000).* ' Peak in R.* 2 Peak in E ~ .
Table 10.6.3 Empirical equationfor the heavy-hole (HH) and light-hole (LH) band-gap energyvariation with temperature Tfor c-CdS.
Electron. 3, 11 (1 994 ).
(1993).
Lett. 64,2 91 (1994).
ParameterC o m m e n t
EO 0) (eV) a ( o4 e V K ) P (K )
2.445 (HH) 3.451 208 n=1 exci ton, epi layer on (1OO)GaAs,
[6.8] T. Nagai, Y. Kanemitsu, M. Ando, T. Kushida, S . Nakamura, Y. Yamada, and T. Taguchi, Phys.Status Solidi B 229,611 (2002).
Table 10.6.4 Empirical equationfor the heavy-hole (HH) and light-hole (LH) band-gap e n e wvariation with temperature Tfor c-CdS.
2.455 (LH) 3.966 222 T=13-200 K [6.8]
2.464 (HH) 20.5 165 n=l exci ton, epi layer on (1 OO)GaAs,
[6.9] T. Nagai, Y. Kanemitsu, M . Ando, T. Kushida, S. Nakamura, Y Yamada, and T. Taguchi, Phys.
2.479 (LH) 25.4 177 T=13-200 K [6.9]
Status Solidi B 229,611 (2002).
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264 Cubic Cadmium Sulphide (cCdS)
Table 10.6.5Spin-orbit-splitofenergy A0f o r e-CdS.*
dn (eV) C o m m e n t
0.079 Calc. [6.10]
-0.07 T=1.7 K 16.111[6.10] M. Willatzen, M. Cardona, and N . E. Chnstensen, Phys. Rev. B 51, 17992 (1 995).[6.11] See, D. W. Niles and H. Hochst, Phys. Rev. B 44, 10965 (1991).*Note that &, may not vary with temperature if one supposes the valence-band rigidity of the 111-V
compounds.
0 Temperature and/or pressure coefficient
Table 10.6.6 Linear temperature and pressure coe8cient.s of the Eo- and Eo+Argap energiesfor e-CdS.
B a n d gap Coefficient Value CommentEO dE, ldT (1O4 e V K )
dE, ldp ( I 0-2 Vl GP a ) 5.5 Calc. [6.12]
4.7 Calc. [6.13]
-0.7 p>6 GPa [6.14]
EO+& dE, IdT (1O4 e V K )
dE, ldp (10-2 V/GPa)
[6.12] K. J. Chang, S. Froyen, and M. L. Cohen, Solidstate Commun. 50, 105 (1984).
[6.13] S.-H. Wei and A . Zunger, Phys. Rev. B 60,540 4 (1999).[6.14] See, B. Ray, ZI-VI Compounds (Pergamon, Oxford, 1969).
10.6.3 Higher-Lying Direct Gap
0 Temperature dependence
Table 10.6.7 Higher-lying d irect-gap energies o r c-CdS at several temperatures.
Value (eV )B a n d g a p
T=90 K [6.15]
El 5 O 5.1E2 6.4,6.9
EO’ 7.4
El’ 8.3
T=300 K [6,16]
[6.15] Ph. H ofinann, K. Horn, A. M . Bradshaw, R. L. Johnson, D.Fuchs, and M . Cardona, Phys. Rev. 47,
[6.16] U. Rossow, T. Werninghaus, D. R. T. Zahn, W. Richter, and K. Horn, Thin Solid Films 233, 1761639 (1 993).
( 1 993).
10.6.4 Lowest Indirect Gap0 Theoretical value
Table 10.6.8 Theoretically obtained lowest indirect-gap enevgy or c-CdS (in ev ).~~ ~ ~
E; * l E$ * 2 Ref.
4.04 5.24 [6.17]
4.30 4.72 [6.18]
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10.7 Energy-Band Structure: E lectron and Hole Effect ive M asses 265
Table 10.6.8 Continued.
E: * ' E$ * 2 Ref.
4.13 4.05 [6.19]
4.82 5.08 16.20116.171A . Zunger and A . J. Feeman, Phys . Rev. B 17,4 850 (1978).16.181M.-Z. Huang and W. Y.Ching, J . Phys. C hem. Solids 46,977 (1985).[6.19]Y.Li and P. J. Lin-Chung, Phys. S tatus Solidi B 153,215 (1 989).16.2010.Zakharov, A . Rubio, X. Blase, M. L. Cohen, and S. L. Louie, Phys. Rev. B 50, 10780 (1994).* I rgv (rl;)+~:(~Ic).* 2 r; (rl:)+&c(xlc).
0 Temperature and/or pressure coefficient
Table 10.6.9 Linear pressure co eflcient of the lowest indirect-gap energy o r c-CdS.
Coefficient Value Com men t
dE:ldp (10-2 VIGPa) 4.2 Calc. [6.21]
3.6 Calc. r6.221
d Ez l d p (10-2eVIGPa) -1 .o Calc. [6.21]
-1.4 Calc. [6.22]
16.211K. J. Chang, S. Froyen, and M. L. Cohen, Solid State Com mun. 50, 105 (1 984).16.221 S.-H. Wei and A . Zunger, Phys . Rev. B 60,5404 (1 999).
10.6.5 Conduction-Valley Energy Separation
No detailed data are available for c-CdS.
10.6.6 Direct-Indirect-Gap Transition Pressure
No detailed data are available for c-Cd S.
I0.7 ENERGY-BAND STRUCTURE: ELECTRON ANDI HOLE EFFECTIVE M ASSES
10.7.1 Electron Effective Mass: I'Valley
Theoretical value
Table 10.7.1 Theoretically obtained electron efective mass m erat the r va ll eyfor c-CdS.
m:/mo Technique~~~~ ~ ~
0.14 $sum rule [7.1]
0.209 Linear combination of atom ic orbital method r7.21
17.13 R. Dalven, Phys. Status SolidiB 48, K23 (1971).17.21 M.-Z. H uang and W. Y .Ching,J. Phys. Chem . Solids 46,9 77 (1985).
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266 Cubic Cadmium Sulphide (cCdS)
10.7.2 Electron Effective Mass: Satellite Valley
No detailed data are available for c-CdS.
10.7.3 Hole Effective Mass0 Luttinger's valence-band parameter
Table 10.7.2 Luttinger j . valence-bandparameter fo r c-CdS (in h2/2m0).
n M Y3
4.11 0.77 1.53
*Estimated fiom a plot of Eo versus 3.;; for som e cubic group-IV, 111-V, and 11-VI sem iconductors (seefigure, below).
20
10
012
9
3
I I Fig. 10.7.1 Luttinger's valence-band parameter y, versus
Eo for a num ber of the group-IV, 111-V, and 11-VI
~=0.77,nd yj=1.53 (in A2/2rno).
-
semiconductors in the cubic structure. From this plot,we can estimate y, values for c-CdS to be 84 .11 ,
-a -I I ,
a
0 2 4 6 8Eo (W
0 Band mass, cyclotron mass, etc.
Table 10.7.3 Band (m", mLH), density-of-states heavy-hole (m"*), averaged light-hole (mLH*),and spherically-averaged heavy-hole (m"", and light-hole masses ( m d ) n c-CdS.*
Mass Value (mo)
WZ" ([OOl] direction) 0.39
mLH ([0011 direction) 0.18
m" ([1111direction) 0.95
mLH ([11 1] direction) 0.14
~ H H * 0.68
~ L H * 0.15
~ H H ~ 0.60
mLHS 0.15
*Calculated using a set of the Luttinger's parameters , ~ 4 . 1 1 ,r=0.77, and yj=l.53.
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10.8 Electronic Deformation Potential 267
Spin-orbit-splitoff hole effective mass
Table 10.7.4 Spin -orbit-splitofh ole efective mass msofor c-CdS.
msdmo
*Obtained from the Luttinger’s parameter (ms o= llp ).
10.8 ELECTRONIC DEFORMATION POTENTIAL
10.8.1 Intravalley Deformation Potential:r Point
0 Conduction bandTable 10.8.1 Peonduction-band intravalley deformationpotential acr (=El 3for c-CdS,
a: (eV> Comment
-27.1 Calc. [8.1]
[8.1] A . Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 1 1 (1984).
0 Valence band
Table 10.8.2 r-valence-band deformationpotentials a, b, and dfor c-CdS.
Commenteformation potential (ev )
~ ~~
-17.5 1.6 Calc. [8.2]
0.92 -1.18 Calc. [8.3]
-1.07 Calc. [8.4]
-1.05 Calc. [8.5]
- 4 .7 Exper. [8.6]
[8.2] A . Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984).
[8.3]A. Qteish and R. J. Needs, Phys. Rev. B 45 , 13 17 (1992).[8.4] T. Nakayama, Solid-state Electron. 37 , 1077 (1994).[8.5] R. Said,A. Qteish, and N. Meskini,J . Phys.: Condens. Matter 10 ,87 03 (1998).[8.6] D. W. Niles and H. Hochst, Phys. Rev. B 44, 10965 (1991).
Eo gap
Table 10.8.3 Hydrostatic deformation potential aorfor the EO ap of c-CdS.
-9.6 Calc. [8.7]
-3.77 Calc. [8.8]
-2.27 Calc. [8.9]
-2.94 Calc. [8.10]
+0.43 ExDer. *[8.7] A . Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 1 1 (1984).[8.8] T. Nakayama, Solid-state Electron. 37, 1077 (1 994).[8.9] R. Said,A . Qteish, and N. Meskini,J. Phys.: Condens. Matter 10,8 703 (1998).
[8.10] S.-H. Wei and A. Zunger, Phys. Rev. B 60,5 404 (1999).*Estimated from dEddp value.
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268 Cubic Cadmium Sulphide (cCdS)
[ , $ h ' ) = ~ ~ ( E ) + i ~ ~ ( h ' ) ]nd (b ) complex refractive-index s^
tical Constants of Crystalline and Amophous Semicon-
1 -pectra [n*(E>=n(E>+ik(E>]or c-CdS at 300 K. The nu-
merical data are taken from tabulation by S. Adachi [Op-
0 Optical-phonon deformation potential
Table 10.8.4 Optical-phonon deformation potential do at the I--valence band of c-CdS,
B -7-----,n
:: -
t- ' x 10---*..
6.9 Calc. [8.11]
[8.11] A. Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984) .
10.8.2 Intravalley Deform ation Potential: High-Symmetry Points
No detailed data are available for c-CdS.
10.8.3 Intervalley Deformation Potential
No detailed data are available for c-CdS.
10.9 ELEC TRO N AFFINITY AND SCHOTTKYBARRIER HEIGHT
10.9.1 Electron Affinity
No detailed data are available for c-CdS.
10.9.2 Schottky Barrier Height
N o detailed data are available for c-CdS.
10.10 OPTICAL PROPERTIES
10.10.1 Summary of Optical Dispersion Relations
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10.10 Opt ica l Propert ies
c-CdS (b ) j
-
-
I I
269
0 H E ) and R(E) spectra
I I
0.35 L I I 1
Fig. 10.10.2 (a) Absorption [or(E)] an d (b) nor-mal-incidence reflectivity spectra [R(E)] or c-CdSat 300 K. The numerical data are taken from tabu-lation by s. Adachi [Optical Constants of Crystal-line and Amorphous Semiconductors: NumericalData and Graphical Information (KluwerAcademic, Boston, 1999)l.
10.10.2 The Reststrahlen Region
0 Static and high-frequency dielectric constants
Table 10.10.1 Static a nd high-frequency dielectric constants E~and E, for c-CdS.
E, E, Comment9.8 5.4 T=300 K
* Estimated fiom w-CdS data [ E ~ = ( E ~ ~ E ~ ~ ~ ) ” ~ ,~ S = ( E ~ S ~ ~ ~ ) ’ ” ] .
10.10.3 At or Near the Fundamental Absorption Edge0 Refractive index
Table 10.10.2 Refractive index n near the fund am ental absorption edge of c-CdS at 300 K[lo. ] .
0.51
1.5
2
2.02
2.04
2.06
2.08
2.12.12
2.14
2.479
1.240
0.826
0.620
0.614
0.608
0.602
0.596
0.5900.585
0.579
2.30
2.33
2.37
2.486
2.494
2.503
2.5 13
2.523
2.5322.542
2.551
2.16
2.18
2.2
2.22
2.24
2.26
2.28
2.3
2.322.34
0.574
0.569
0.563
0.558
0.553
0.548
0.544
0.539
0.5340.530
2.563
2.575
2.586
2.599
2.6 14
2.630
2.650
2.673
2.7032.739
[10.11 See, S . Adachi, Optical Constants of Crystalline and Amorphous Semiconductors: NumericalData and Graphical Information (Kluwer Academic, Boston, 1999).
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Cubic Cadmium Sulphide (cCdS)70
Fig. 10.10.3 Refractive index n for c-CdS at T=300 K.The experimental data are taken from S. Adachi [Op-tical Constants of Crystalline and Amorphous Semi-conductors: Numerical Data and Graphical Informa-tion (Kluw er Academic, Boston, 1999)l. The solid linerepresents the calculated result usingn2=4.46+[0.806A2/(A2-0.203)]ith A n pm.
0 0.5 1.0 1.5 2.0Photon energy (eV)
0 Fundamental absorption edge
0 As-grown
2.3 2.4 2.5 2.6 2.7
2.5
Fig.10.10.4
(ahv ) ~
ersus photon energy h v plots for as-grownand two annealed samples. Polycrystalline thin films in theceCdS phase were grown on glass substrates at 80fl"C bychem ical bath deposition. Solid-solid phase transform ation fromthe cubic, zinc-blende or sphalerite metastable modification ofCdS (c-CdS) to the hexagonal, wurtzite stable phase (w-CdS)gradually occurred by annealing in A r + S 2 in the temperaturerange 100-550°C. The extrapolation of the straight line to the h v
axis gives EO.[From 0.Zelaya-Angel and R. Lozada-Morales,Phys. Rev. B 62, 3064 (2000).]
10.10.4 The Interband Transition Region0 Fundam ental optical spectra
Fig. 10.10.5 Complex dielectric function,~ ( E ) = E ~ ( E ) + ~ E ~ ( E ) ,undamental reflectivity,R(E) , and energy-loss function, -ImE'(E),for c-CdS at 300 K. The experimental dataare taken from tabu lation by S. Adachi [Op-tical Constants of Crystalline and Amor-phous Semiconductors: Numerical Data andGraphical Information (Kluwer Academic,Boston, 1999)l.
10
8
6
2
0
Q 4
0.4 I I I I I 10.20
0 ' I I / I I I ' 0
0 1 2 3 4 5 6Photon energy (eV)
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10.11 Elastoopt ic , E lect roopt ic , and Nonl inear Opt ical Proper t ies 27 1
10.10.5 Free-Carrier Absorption and Related Phenomena
No detailed data are available for c-CdS .
10.11 ELASTOOPTIC, ELECTROOPTIC, ANDNONLINEAR OPTICAL PROPERTIES
10.11.1 Elastooptic EffectNo detailed data are available for c-CdS.
10.11.2 Linear Electrooptic ConstantNo detailed data are available for c-CdS.
10.11.3 Quadratic Electrooptic ConstantNo detailed data are available for c-CdS.
10.11.4 Franz-Keldysh EffectNo detailed data are available for c-CdS.
10.1 1.5 Nonlinear Optical ConstantSecond-order nonlinear optical susceptibility
Table 10.11.1 Theoretical second-order nonlinear optical susceptibilityx;;:-20; w ;w ) n thestatic limit ( tZw-4 ev)for c-CdS,
7.4 r11.11
[11, I ] M.-Z. Huang and W. Y. Ching, Phys. Rev. B 47,9464 (1993).* 1 m N = 3x 104/4nesu.
0 Third-order nonlinear optical susceptibility
Table 10.11.2 Theoretical third-order nonlinear optical susceptibilityX$ (-313; w ,w ,w ) n thestatic limit @w+O ev)for c-CdS.
1 oo 0.57 F11.21
[11.21W. Y. Ching and M.-Z. Huang, Phys. Rev.B 47,9479 (1993).
* 1 m N 2= 9x OS/4nesu.
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272 Cubic Cadmium Sulphide ( c C d S )
10.12 CAR RIER TRANSPORT PROPERTIES
10.12.1 Low-Field Mobility: Electrons
Table 10.12.1 300-K (&*OK) and pea k H all mobilities (ppeuk)o r electrons in c-CdS.
Mobility Value (c m 2 N ) Comment
p300K 70-85 MO CVD-grown layer on GaAs(100)
n=5.Ox 1Ol8-6.5x 1019 ~ m ' ~12.13
Pp e a k
[12.11K. Yasuda, H. B. Samion, M. Miyata, N. Araki, Y. M asuda, and Y. Tom ita,J. Cryst.Growth 222,
477 (2001).
10.12.2 Low-Field Mobility: Holes
No detailed data are available for c-CdS.
10.12.3 High-Field Transport: Electrons
0 LO-phonon-scattering-limited electron saturation drift velocity
Table 10.12.2 Calculated LO-phonon-scattering-limited electron saturation driftvelocity v,,,,,in the lowest-conduction -band valley afor c-CdS at 300 K. *
I-
e,sat 3 4I
*Calculated w ith r =0.14mo an d a 0 = 3 0 3 cm-'.
10.12.4 High-Field Transport: Holes
No detailed data are available for c-CdS.
10.12.5 Minority-Carrier Transport: Electrons in p-Type Materials
N o detailed data are available for c-CdS .
10.12.6 Minority-Carrier Transport: Holes in n-Type Materials
N o detailed data are available for c-CdS.
10.12.7 Impact Ionization Coefficient
N o detailed data are available for c-CdS.