CdSe (wurtzite)

Crystal Structure

 

 

  Fractional Coordinates Orthogonal Coordinates
  Label Elmt x y z xor[Å] yor[Å] zor[Å]
1. T1 Cd 0.6667 0.3333 0.0000 -1.738 -0.109 1.768
2. T1 Cd 0.3333 0.6667 0.5000 0.824 3.199 2.747
3. T1 Cd 0.6667 0.3333 1.0000 -1.415 6.859 2.513
4. T2 Se 0.6667 0.3333 0.3750 -1.617 2.504 2.048
5. T2 Se 0.3333 0.6667 0.8750 0.945 5.812 3.027

 

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] 0 1 0 3.72261 23.8828 2.01941e-001 100.0 6 1
[2] 0 0 2 3.50760 25.3704 1.19461e-001 59.2 2 4
[3] 0 1 1 3.28831 27.0935 1.53355e-001 75.9 12 2
[4] 0 1 2 2.55288 35.1217 7.60123e-002 37.6 12 5
[5] 1 1 0 2.14925 42.0016 1.76915e-001 87.6 6 2
[6] 0 1 3 1.98014 45.7830 1.76516e-001 87.4 12 10
[7] 0 2 0 1.86131 48.8904 2.81154e-002 13.9 6 4
[8] 1 1 2 1.83259 49.7080 1.10330e-001 54.6 12 6
[9] 0 2 1 1.79906 50.6993 2.62001e-002 13.0 12 5
[10] 0 0 4 1.75380 52.1043 9.71422e-004 0.5 2 16
[11] 0 2 2 1.64416 55.8710 1.92128e-002 9.5 12 8
[12] 0 1 4 1.58655 58.0890 1.00406e-003 0.5 12 17
[13] 0 2 3 1.45629 63.8640 6.32987e-002 31.3 12 13
[14] 1 2 0 1.40701 66.3825 2.18411e-002 10.8 12 5
[15] 1 2 1 1.37954 67.8819 2.09435e-002 10.4 24 6
[16] 1 1 4 1.35881 69.0623 2.22018e-003 1.1 12 18
[17] 0 1 5 1.31289 71.8441 4.43706e-002 22.0 12 26
[18] 1 2 2 1.30587 72.2909 1.74150e-002 8.6 24 9
[19] 0 2 4 1.27644 74.2329 4.40427e-004 0.2 12 20
[20] 0 3 0 1.24087 76.7395 2.86434e-002 14.2 6 9
[21] 1 2 3 1.20560 79.4187 6.73141e-002 33.3 24 14
[22] 0 3 2 1.16983 82.3607 2.45689e-002 12.2 12 13
[23] 0 0 6 1.16920 82.4144 4.08848e-003 2.0 2 36
[24] 0 2 5 1.12039 86.8627 2.73303e-002 13.5 12 29
[25] 0 1 6 1.11547 87.3415 5.39674e-003 2.7 12 37
[26] 1 2 4 1.09748 89.1489 5.54168e-004 0.3 24 21
[27] 2 2 0 1.07463 91.5755 1.92663e-002 9.5 6 8
[28] 1 3 0 1.03247 96.4951 8.94575e-003 4.4 12 10
[29] 2 2 2 1.02749 97.1194 1.82529e-002 9.0 12 12
[30] 1 1 6 1.02706 97.1730 1.82418e-002 9.0 12 38
[31] 1 3 1 1.02146 97.8876 8.99105e-003 4.5 24 11
[32] 0 3 4 1.01296 98.9977 9.71735e-004 0.5 12 25

PV Applications

 

Basic Parameters at 300 K

Crystal structure: Wurtzite 1
Group of symmetry: P6_3mc 1
Number of atoms in 1 cm3: 3.56*1026 1
 
Unit cell volume: 112.2547 Å3 1
Atoms per unit cell: 4 1
Auger recombination coefficient C:    
Debye temperature: 181.7 K T = 0 K 2
Density: 5.81 g/cm3 T = 300 K 2
Dielectric constants: ɛ(0)|| = 10.16 T = 300 K 2
  9.29 T = 100 K  
  ɛ(0)⊥ = 9.29 T = 300 K  
  9.15 T = 100 K  
  ɛ(∞)|| = 6.30 T = 300 K  
  6.30 T = 100 K  
  ɛ(∞) ⊥ = 6.20 T = 300 K  
  6.20 T = 100 K  
Effective electron density:      
Effective electron masses: mn = 0.12 m0   2
Effective hole density:      
Effective hole masses: mhh = 2.14 m0 [111] direction 2
  0.9 m0 [100] direction  
  1.7 m0 [110] direction  
  mlh = 0.16 m0 [111] direction  
  0.18 m0 [100] direction  
  0..16 m0 [110] direction  
  mso = 0.12 m0 split-off band  
Lattice constants: a=b= 4.2985 Å   1
  c = 7.0152 Å    

Band structure and carrier concentration

Temperature Dependences

Temperature dependence on annealed CdSe thin films 3

Thin Films Crystalite size (Å) Band Gap 'Eg' (eV) Electrical resistivity (Ωcm) Activation energy Ea (eV)
HR LR
As-deposited 40 2.3 3.25 × 105 0.86 0.34
373 K 60 2.0 9.58 × 104 0.79 0.31
473 K 80 1.8 5.38 × 104 0.72 0.27
573 K 120 1.8 8.23 × 103 0.69 0.18
673 K 180 1.7 1.17 × 103 0.65 0.16

      HR: High temperature region LR: Low temperature region

Plot of absorbance vs. wavelength for CdSe thin films can be found in:3

Plot of log ρ vs. (1000/T) of CdSe thin films can be found in: 3    

Electrical Properties

        Basic Parameters of Electrical Properties

                Energy gap:                                                        1.74 eV                 T = 300 K              2                                                                       

Energy spin-orbital splitting:                           470 meV                                               2        

Intrinsic carrier concentration:                        6*1013 cm-3         T = 800 K              2

                                                                              6*1016 cm-3         T = 1300 K                           

 

Carrier mobility:                                                                   μn = 660 cm2/Vs                T = 300 K              2

                                                                                                         5000 cm2/Vs              T = 80 K

                                                                                                         200  cm2/Vs               T = 800 K             

 

Electron drift mobility:                                                   μdr,n = 720 cm2/Vs             T = 300 K              2        

Hole Hall mobility:                                                            μH,p = 40 cm2/Vs             T = 300 K              2

    

Thermal properties

            Heat capacity:                                    Cp [J mol-1 K-1] = 48.46 + 5.87-3 *T – 58154*T-2       2

            Thermal conductivity:                    κL = 0.09 W cm-1 K-1                                                          2

Mechanical properties, elastic constants, lattice vibrations

        Basic Parameters                                          

Density:                                               5.81 g/cm3           T = 300 K                              2                                                                                 

                                                                                                                                                                                           

        Elastic Constants

                Elastic Constants:                                              c11 = 74.6 Gpa    T = 300 K                              2

                                                                                                c12 = 46.1 Gpa                                                   

                                                                                                c33 = 81.7 Gpa

                                                                                                c44 = 13.0 Gpa

                                                                                                c66 = 14.3 Gpa                                                   

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 [email protected] with such suggestions.