ZnSe
Basic Info
Section titled “Basic Info”ZnSe is a light yellow binary solid compound that is rarely occurs in nature. It can be made in hexagonal and cubic crystal structures. Zinc selenide is used as a blue light source in light-emitting diodes and diode lasers. It is also used as infrared laser gain medium and as an infrared optical material. ZnSe activated with tellurium is used in x-ray and gamma ray detectors as a scintillator. [9]
Crystal Structure
Section titled “Crystal Structure”
| Fractional Coordinates | Orthogonal Coordinates | |||||||
|---|---|---|---|---|---|---|---|---|
| Label | Elmt | x | y | z | xor[Å] | yor[Å] | zor[Å] | |
| 1. | T2 | Se | 0.2500 | 0.2500 | 0.2500 | -0.863 | -1.331 | -1.873 |
| 2. | T2 | Se | 0.2500 | 0.7500 | 0.7500 | 0.100 | -3.980 | -4.722 |
| 3. | T2 | Se | 0.7500 | 0.7500 | 0.2500 | -2.657 | -1.164 | -5.453 |
| 4. | T2 | Se | 0.7500 | 0.2500 | 0.7500 | -3.482 | -4.171 | -2.935 |
| 5. | T1 | Zn | 0.0000 | 0.0000 | 0.0000 | 0.000 | 0.000 | -0.000 |
| 6. | T1 | Zn | 0.0000 | 0.5000 | 0.5000 | 0.963 | -2.649 | -2.849 |
| 7. | T1 | Zn | 0.5000 | 0.5000 | 0.0000 | -1.794 | 0.167 | -3.580 |
| 8. | T1 | Zn | 0.5000 | 0.0000 | 0.5000 | -2.620 | -2.841 | -1.063 |
| 9. | T1 | Zn | 1.0000 | 0.0000 | 0.0000 | -5.376 | -0.025 | -1.793 |
| 10. | T1 | Zn | 1.0000 | 0.5000 | 0.5000 | -4.414 | -2.674 | -4.642 |
| 11. | T1 | Zn | 0.0000 | 1.0000 | 0.0000 | 1.788 | 0.358 | -5.366 |
| 12. | T1 | Zn | 0.5000 | 1.0000 | 0.5000 | -0.831 | -2.482 | -6.429 |
| 13. | T1 | Zn | 1.0000 | 1.0000 | 0.0000 | -3.588 | 0.333 | -7.159 |
| 14. | T1 | Zn | 0.0000 | 0.0000 | 1.0000 | 0.137 | -5.656 | -0.332 |
| 15. | T1 | Zn | 0.5000 | 0.5000 | 1.0000 | -1.657 | -5.490 | -3.912 |
| 16. | T1 | Zn | 1.0000 | 0.0000 | 1.0000 | -5.239 | -5.681 | -2.125 |
| 17. | T1 | Zn | 0.0000 | 1.0000 | 1.0000 | 1.925 | -5.298 | -5.698 |
| 18. | T1 | Zn | 1.0000 | 1.0000 | 1.0000 | -3.451 | -5.323 | -7.491 |
Theoretical diffraction data using a Cu Kα monochromatic source.
(m is the multiplicity and N is the maximum number of flexions)
| ref no. | h | k | l | d(hkl) | 2-Theta | Intensity | I/Imax | m | N |
|---|---|---|---|---|---|---|---|---|---|
| [ 1] | 1 | 1 | 1 | 3.27219 | 27.2296 | 3.56799e-001 | 100.0 | 8 | 3 |
| [ 2] | 0 | 0 | 2 | 2.83380 | 31.5438 | 1.03393e-003 | 0.3 | 6 | 4 |
| [ 3] | 0 | 2 | 2 | 2.00380 | 45.2123 | 2.62259e-001 | 73.5 | 12 | 8 |
| [ 4] | 1 | 1 | 3 | 1.70885 | 53.5827 | 1.57080e-001 | 44.0 | 24 | 11 |
| [ 5] | 2 | 2 | 2 | 1.63610 | 56.1706 | 3.14514e-004 | 0.1 | 8 | 12 |
| [ 6] | 0 | 0 | 4 | 1.41690 | 65.8603 | 4.10933e-002 | 11.5 | 6 | 16 |
| [ 7] | 1 | 3 | 3 | 1.30024 | 72.6539 | 6.12994e-002 | 17.2 | 24 | 19 |
| [ 8] | 0 | 2 | 4 | 1.26731 | 74.8585 | 6.43795e-004 | 0.2 | 24 | 20 |
| [ 9] | 2 | 2 | 4 | 1.15689 | 83.4861 | 8.34838e-002 | 23.4 | 24 | 24 |
| [ 10] | 1 | 1 | 5 | 1.09073 | 89.8496 | 4.77530e-002 | 13.4 | 32 | 27 |
| [ 11] | 0 | 4 | 4 | 1.00190 | 100.4906 | 3.01446e-002 | 8.4 | 12 | 32 |
PV Applications
Section titled “PV Applications”ZnSe thin films are prepared primarily by molecular beam epitaxy, chemical vapor deposition, chemical vapor deposition, and vacuum evaporation. Electrodeposition is a simple, low cost and a viable method for producing good quality films.[Chandramohan1997]
ZeSe films prepared by chemical vapor deposition have a buffer layer that has reached total area efficiencies of up to 9.6% (under AM 1.5 illumination), an open circuit voltage of 482 mV, a short circuit current of 31.0 mA/cm2 and a fill factor reaching 64%. [rumberg2000]
Basic Parameters at 300 K
Section titled “Basic Parameters at 300 K”| Crystal structure: | Sphalerite | [Wyckoff1963] |
| Group of symmetry: | F-43m | [Wyckoff1963] |
| Number of atoms in 1 cm3: | 4.39*1026 | [Wyckoff1963] |
| Unit cell volume: | 182.05 Å3 | [Wyckoff1963] |
| Atoms per unit cell: | 8 | [Wyckoff1963] |
| Debye temperature: | 339(2) K | [Madelung2004] |
| Density: | 5.266 g/cm3 | [Wyckoff1963] |
| Dielectric constant (static): | 8.6 | [adachi1991] |
| Dielectric constant (high frequency): | 5.7 | [adachi1991] |
| Effective electron masses: | (0.16 ± 0.01)me | [merz1972] |
| Effective hole masses: | 0.75 mo | [Madelung2004] |
| Lattice constant: | a = 5.667 Å | [Wyckoff1963] |
| Optical phonon energy (longitudinal): | 0.0314 eV | [531] |
| Conductivity: | n-type | [merz1972] |
Temperature Dependences
Section titled “Temperature Dependences”Graph of electron concentration vs temperature may be found in M. Aven, High Electron Mobility in Zinc Selenide Through Low Temperature Annealing. J. Appl. Phys. 42, 1204 (1971); doi: 10.1063/1.1660167 [531]
Donors and Acceptors
Section titled “Donors and Acceptors”Donors: Al, Cl, Ga, In, F, Br [merz1972],[Bube1958]
Acceptors: Cu, Ag, Sb [Bube1958]
Ionization energy of shallow donors [Madelung2004]
Ed(LiI) 15(1) meV T= 4.2 K
Ed(NaI) 16(1) meV
Ed(Al) 26.3 meV
Ed(Ga) 27 meV
Ed(In) 28.1 meV
Ed(F) 29.3 meV
Ed(Cl) 26.1 meV
Ed(I) 30.4 meV
Ionization evergy of shallow acceptors
Ea(Li) 118(2) meV T = 4.2 K
Ea(Na) 98(2) meV
Ea(K) 94(2) meV
Ea(N) 112 meV T = 4.2 K
Ea(P) 80…92 meV T = 4.2 K
Ea(As) 125 meV T = 77 K
Ea(Sb) 69 meV T = 30 K
Ea(Rb) 89(2) meV T = 4.2 K
Ea(Cs) 74(2) meV
Ea(O) 80 meV T = 4 K
Ea(VZn) 218 meV T = 4 K
Electrical Properties
Section titled “Electrical Properties”Basic Parameters of Electrical Properties
Section titled “Basic Parameters of Electrical Properties”Energy gap: 2.81 eV [Chandramohan1997]
Energy spin-orbital splitting: ∆0 (Γ8v- Γ7v) 0.42 eV T=295 K [Madelung2004]
∆1 (Γ4,5v- Γ6v) 0.20 eV T=300 K [Madelung2004]
Donor concentration: 1016 cm-3 [531]
Carrier mobility: μn = up to 400 cm2/Vs T=300K [Madelung2004]
μp = 110 cm2/Vs T=300K [Madelung2004]
Intrinsic resistivity: ~1012 Ω cm [jones1976]
Mobility and Hall Effect
Section titled “Mobility and Hall Effect”
Hall mobility: 530 cm2/ V*s (T=300 K) [jones1976]
12,000 cm2/ V*s (T=60 K) [jones1976]
Absorption coefficient: 104 cm-1 [Chandramohan1997]
Mobilities and mobility ratios as well as a graph of electron hall mobility vs temperature may be found in:
M. Aven, High Electron Mobility in Zinc Selenide Through Low Temperature Annealing. J. Appl. Phys. 42, 1204 (1971); doi: 10.1063/1.1660167 [531]
Optical properties
Section titled “Optical properties”Refractive index: Graph of refractive index and absorption index vs. photon energy may be found in [Madelung2004]
Thermal properties
Section titled “Thermal properties”Coefficient of linear thermal expansion: α = 7.4*10-6 K-1 [Madelung2004]
Heat capacity: Cp = 51.88 J/Mol*K [Madelung2004]
Thermal conductivity κ = 0.19 W K-1 cm-1 T=300K [Madelung2004]
Graphs of ZnSe's thermal properties may be found in Madelung [Madelung2004]
Mechanical properties, elastic constants, lattice vibrations
Section titled “Mechanical properties, elastic constants, lattice vibrations”Basic Parameters
Section titled “Basic Parameters”Bulk modulus: 62.4(7) GPa [Madelung2004]
Density: 5.266 g/cm3 [Madelung2004]
Elastic Constants
Section titled “Elastic Constants”Elastic Constants: C11 = 90.3(19) GPa [Madelung2004]
C12 = 53.6(23) Gpa [Madelung2004]
C44 = 39.4(12) Gpa [Madelung2004]
Phonon Frequencies
Section titled “Phonon Frequencies”VLO(Γ) 7.59 THz T=300 K [Madelung2004]
VTO(Γ) 6.39 THz T=300 K
Phonon Energies
Section titled “Phonon Energies”HvLO(Γ1) 30.99 meV [Madelung2004]
HvTO(Γ15) 25.17 meV
HvLA(Γ) 19.8 meV
HvTA(Γ) 8.0 meV
HvLO(X) 27.64 meV
HvTO 25.54 meV
HvLA 23.55 meV
HvLO(L) 27.77 meV
HvTO 25.54 meV
Hv(W3) 24.9 meV
Hv(W1) 18.59 meV
Hv(W’2) 11.53 meV
Hv(W”2) 26.53. meV
Hv(W’4) 14.26 meV
Hv(W”4) 24.61 meV
Developed at the University of Utah primarily by undergraduate students Jeff Provost and Carina Hahn working with Prof. Mike Scarpulla. Caitlin Arndt, Christian Robert, Katie Furse, Jash Sayani, and Liz Lund also contributed. The work was fully supported by the US National Science Foundation under the Materials World Network program award 1008302. These pages are a work in progress and we solicit input from knowledgeable parties around the world for more accurate or additional information. Contact earthabundantpv@eng.utah.edu with such suggestions.
References
Section titled “References”- R. Chandramohan, C. Sanjeeviraja and T. Mahalingam, “Preparation of Zinc Selenide Thin Films by Electrodeposition Technique for Solar Cell Applications,” physica status solidi (a), vol. 163, no. 2, pp. R11 - R12, 1997. https://doi.org/10.1002/(ISSN)1521-396X10.1002/1521-396X(199710)163:2<>1.0.CO;2-U10.1002/1521-396X(199710)163:2<R11::AID-PSSA999911>3.0.CO;2-3
- A. Rumberg et al., “ZnSe thin films grown by chemical vapour deposition for application as buffer layer in CIGSS solar cells,” Thin Solid Films, vol. 361-362, pp. 172 - 176, 2000. https://doi.org/10.1016/S0040-6090(99)00790-7
- R. Wyckoff, “Crystal Structures 1,” Interscience Publishers, vol. 1, 1963. http://rruff.geo.arizona.edu/AMS/AMC_text_files/13434_amc.txt
- O. Madelung, “Semiconductors Data Handbook,” Springer, 2004. http://www.amazon.com/Semiconductors-Data-Handbook-Otfried-Madelung/dp/3540404880
- S. Adachi and T. Taguchi, “Optical properties of ZnSe,” Physical Review B, vol. 43, no. 12, pp. 9569 - 9577, 1991. https://doi.org/10.1103/PhysRevB.43.9569
- J. Merz et al., “Optical Properties of Substitutional Donors in ZnSe,” Physical Review B, vol. 6, no. 2, pp. 545 - 556, 1972. https://doi.org/10.1103/PhysRevB.6.545
- M. Aven, “High Electron Mobility in Zinc Selenide Through Low-Temperature Annealing,” Journal of Applied Physics, vol. 42, no. 3, pp. 1204, 1971. https://doi.org/10.1063/1.1660167
- R. Bube and E. Lind, “Photoconductivity of Zinc Selenide Crystals and a Correlation of Donor and Acceptor Levels in II-VI Photoconductors,” Phys. Rev., vol. 110, pp. 1040–1049, 1958. https://doi.org/10.1103/PhysRev.110.1040
- G. Jones and J. Woods, “The electrical properties of zinc selenide,” Journal of Physics D: Applied Physics, vol. 9, no. 5, pp. 799 - 810, 1976. https://doi.org/10.1088/0022-3727/9/5/013