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References

  1. J. C. Phillips, Bonds and Bands in Semiconductors (Academic, New York, 1973).

    Google Scholar 

  2. D. R. Lide, CRC Handbook of Chemistry and Physics, 78th Edition (CRC Press, Boca Raton, 1997).

    Google Scholar 

  3. J. C. Jamieson and H. H. Demarest, Jr., J. Phys. Chem. Solids 41, 963 (1980).

    CAS  Google Scholar 

  4. S. C. Yu, I. L. Spain, and E. F. Skelton, Solid State Commun. 25, 49 (1978).

    CAS  Google Scholar 

  5. A. Onodera and A. Ohtani, J. Appl. Phys. 51, 2581 (1980).

    CAS  Google Scholar 

  6. W. H. Gust, J. Appl. Phys. 53, 4843 (1982).

    CAS  Google Scholar 

  7. S. Ves, U. Schwarz, N. E. Christensen, K. Syassen, and M. Cardona, Phys. Rev. B 42, 9113 (1990).

    Article  CAS  Google Scholar 

  8. A. Béliveau and C. Carlone, Phys. Rev. B 44, 3650 (1991).

    Article  Google Scholar 

  9. Y. Zhou, A. J. Campbell, and D. L. Heinz, J. Phys. Chem. Solids 52, 821 (1991).

    CAS  Google Scholar 

  10. M. Uchino, T. Mashimo, M. Kodama, T. Kobayashi, E. Takasawa, T. Sekine, Y. Noguchi, H. Hikosaka, K. Fukuoka, Y. Syono, T. Kondo, and T. Yagi, J. Phys. Chem. Solids 60, 827 (1999).

    CAS  Google Scholar 

  11. S. Desgreniers, L. Beaulieu, and I. Lepage, Phys. Rev. B 61, 8726 (2000).

    Article  CAS  Google Scholar 

  12. B. N. Oshcherin, Phys. Status Solidi A 34, K181 (1976).

    CAS  Google Scholar 

  13. See, J. A. Van Vechten, Phys Rev. B 7, 1479 (1973).

    Google Scholar 

  14. See, B. R. Nag, J. Electron. Mater. 26, 70 (1997).

    CAS  Google Scholar 

  15. G. A. Slack, Phys. Rev. B 6, 3791 (1972).

    Article  CAS  Google Scholar 

  16. Numerical Data and Functional Relationships in Science and Technology, edited by K.-H. Hellwege and A. M. Hellwege, Landolt-Börnstein, New Series, Group III, Vol. 18 (Springer, Berlin, 1984).

    Google Scholar 

  17. Numerical Data and Functional Relationships in Science and Technology, edited by K.-H. Hellwege and A. M. Hellwege, Landolt-Börnstein, New Series, Group III, Vol. 11 (Springer, Berlin, 1979).

    Google Scholar 

  18. Theor. [A. Nazzal and A. Qteish, Phys. Rev. B 53, 8262 (1996)].

    Google Scholar 

  19. Exper. [J. C. Jamieson and H. H. Demarest, Jr., J. Phys. Chem. Solids 41, 963 (1980)].

    Google Scholar 

  20. Exper. [M. Uchino, T. Mashimo, M. Kodama, T. Kobayashi, E. Takasawa, T. Sekine, Y. Noguchi, H. Hikosaka, K. Fukuoka, Y. Syono, T. Kondo, and T. Yagi, J. Phys. Chem. Solids 60, 827 (1999)].

    Google Scholar 

  21. Exper. [S. Desgreniers, L. Beaulieu, and I. Lepage, Phys. Rev. B 61, 8726 (2000)].

    Google Scholar 

  22. See, L. Garbato and A. Rucci, Phil. Mag. 35, 1681 (1977).

    Google Scholar 

  23. N. Vagelatos, D. Wehe, and J. S. King, J. Chem. Phys. 60, 3613 (1974).

    Article  CAS  Google Scholar 

  24. Numerical Data and Functional Relationships in Science and Technology, edited by O. Madelung, M. Schulz, and H. Weiss, Landolt-Börnstein, New Series, Group III, Vol. 17, Pt. b (Springer, Berlin, 1982).

    Google Scholar 

  25. A. Memon and D. B. Tanner, Phys. Status Solidi B 127, 49 (1985).

    Google Scholar 

  26. M. Siakavellas, A. G. Kontos, and E. Anastassakis, J. Appl. Phys. 84, 517 (1998).

    Article  CAS  Google Scholar 

  27. M. Cardona, J. Phys. (Paris) 45, C8–29 (1984).

    Google Scholar 

  28. See, D. N. Talwar, M. Vandevyver, K. Kunc, and M. Zigone, Phys. Rev. B 24, 741 (1981).

    Google Scholar 

  29. M. Siakavellas, A. G. Kontos, and E. Anastassakis, J. Appl. Phys. 84, 517 (1998).

    Article  CAS  Google Scholar 

  30. M. Siakavellas, A. G. Kontos, and E. Anastassakis, J. Appl. Phys. 84, 517 (1998).

    Article  CAS  Google Scholar 

  31. D. Berlincourt, H. Jaffe, and L. R. Shiozawa, Phys. Rev. 129, 1009 (1963).

    Article  CAS  Google Scholar 

  32. E. Kartheuser, in Polarons in Ionic Crystals and Polar Semiconductors, edited by J. T. Devreese (North-Holland, Amsterdam, 1972), p. 717.

    Google Scholar 

  33. Y. Imanaka and N. Miura, Phys. Rev. B 50, 14065 (1994).

    Article  CAS  Google Scholar 

  34. O. Zakharov, A. Rubio, X. Blase, M. L. Cohen, and S. G. Louie, Phys. Rev. B 50, 10780 (1994).

    Article  CAS  Google Scholar 

  35. O. Kanehisa, M. Shiiki, M. Migita, and H. Yamamoto, J. Cryst. Growth 86, 367 (1988).

    CAS  Google Scholar 

  36. T. K. Tran, W. Park, W. Tong, M. M. Kyi, B. K. Wagner, and C. J. Summers, J. Appl. Phys. 81, 2803 (1997).

    Article  CAS  Google Scholar 

  37. R. Pässler, E. Griebl, H. Riepl, G. Lautner, S. Bauer, H. Preis, W. Gebhardt, B. Buda, D. J. As, D. Schikora, K. Lischka, K. Papagelis, and S. Ves, J. Appl. Phys. 86, 4403 (1999).

    Google Scholar 

  38. K. A. Dmitrenko, L. V. Taranenko, S. G. Shevel’, and A. V. Marinchenko, Sov. Phys. Semicond. 19, 487 (1985).

    Google Scholar 

  39. R. Pässler, E. Griebl, H. Riepl, G. Lautner, S. Bauer, H. Preis, W. Gebhardt, B. Buda, D. J. As, D. Schikora, K. Lischka, K. Papagelis, and S. Ves, J. Appl. Phys. 86, 4403 (1999).

    Google Scholar 

  40. M. Fernández, P. Prete, N. Lovergine, A. M. Mancini, R. Cingolani, L. Vasanelli, and M. R. Perrone, Phys. Rev. B 55, 7660 (1997).

    Article  Google Scholar 

  41. K. P. O’Donnell and P. G. Middleton, in Properties of Wide Bandgap II–VI Semiconductors, EMIS Datareviews Series No. 17, edited by R. Bhargava (INSPEC, London, 1997), p. 33.

    Google Scholar 

  42. R. Pässler, Phys. Status Solidi B 216, 975 (1999).

    Google Scholar 

  43. R. Pässler, J. Appl. Phys. 89, 6235 (2001).

    Google Scholar 

  44. E. Matatagui, A. G. Thompson, and M. Cardona, Phys. Rev. 176, 950 (1968).

    Article  CAS  Google Scholar 

  45. M. Fernández, P. Prete, N. Lovergine, A. M. Mancini, R. Cingolani, L. Vasanelli, and M. R. Perrone, Phys. Rev. B 55, 7660 (1997).

    Article  Google Scholar 

  46. S. Ves, U. Schwarz, N. E. Christensen, K. Syassen, and M. Cardona, Phys. Rev. B 42, 9113 (1990).

    Article  CAS  Google Scholar 

  47. A. Mang, K. Reimann, St. Rübenacke, and M. Steube, Phys. Rev. B 53, 16283 (1996).

    Article  CAS  Google Scholar 

  48. J. Camassel and D. Auvergne, Phys. Rev. B 12, 3258 (1975).

    Article  CAS  Google Scholar 

  49. V. V. Sobolev, V. I. Donetskikh, and E. F. Zagainov, Sov. Phys. Semicond. 12, 646 (1978).

    Google Scholar 

  50. A. Abounadi, M. Di Blasio, D. Bouchara, J. Calas, M. Averous, O. Briot, N. Briot, T. Cloitre, R. L. Aulombard, and B. Gil, Phys. Rev. B 50, 11677 (1994).

    Article  CAS  Google Scholar 

  51. M. Fernández, P. Prete, N. Lovergine, A. M. Mancini, R. Cingolani, L. Vasanelli, and M. R. Perrone, Phys. Rev. B 55, 7660 (1997).

    Article  Google Scholar 

  52. R. Pässler, E. Griebl, H. Riepl, G. Lautner, S. Bauer, H. Preis, W. Gebhardt, B. Buda, D. J. As, D. Schikora, K. Lischka, K. Papagelis, and S. Ves, J. Appl. Phys. 86, 4403 (1999).

    Google Scholar 

  53. D. L. Camphausen, G. A. N. Connell, and W. Paul, Phys. Rev. Lett. 26, 184 (1971).

    Article  CAS  Google Scholar 

  54. See, S. Adachi, Optical Constants of Crystalline and Amorphous Semiconductors: Numerical Data and Graphical Information (Kluwer Academic, Boston, 1999).

    Google Scholar 

  55. D. Theis, J. Phys. Chem. Solids 38, 1125 (1977).

    CAS  Google Scholar 

  56. D. L. Camphausen, G. A. N. Connell, and W. Paul, Phys. Rev. Lett. 26, 184 (1971).

    Article  CAS  Google Scholar 

  57. Y. F. Tsay, S. S. Mitra, and B. Bendow, Phys. Rev. B 10, 1476 (1974).

    Article  CAS  Google Scholar 

  58. M.-Z. Huang and W. Y. Ching, J. Phys. Chem. Solids 46, 977 (1985).

    CAS  Google Scholar 

  59. Y. Li and P. J. Lin-Chung, Phys. Status Solidi B 153, 215 (1989).

    CAS  Google Scholar 

  60. O. Zakharov, A. Rubio, X. Blase, M. L. Cohen, and S. L. Louie, Phys. Rev. B 50, 10780 (1994).

    Article  CAS  Google Scholar 

  61. D. L. Camphausen, G. A. N. Connell, and W. Paul, Phys. Rev. Lett. 26, 184 (1971).

    Article  CAS  Google Scholar 

  62. Y. F. Tsay, S. S. Mitra, and B. Bendow, Phys. Rev. B 10, 1476 (1974).

    Article  CAS  Google Scholar 

  63. S.-H. Wei and A. Zunger, Phys. Rev. B 60, 5404 (1999).

    CAS  Google Scholar 

  64. M. Cardona, J. Phys. Chem. Solids 24, 1543 (1963).

    CAS  Google Scholar 

  65. R. L. Bowers and G. D. Mahan, Phys. Rev. 185, 1073 (1969).

    Article  CAS  Google Scholar 

  66. P. Lawaetz, Phys. Rev. B 4, 3460 (1971).

    Article  Google Scholar 

  67. C. S. Wang and B. M. Klein, Phys. Rev. B 24, 3393 (1981).

    CAS  Google Scholar 

  68. M.-Z. Huang and W. Y. Ching, J. Phys. Chem. Solids 46, 977 (1985).

    CAS  Google Scholar 

  69. H. Kukimoto, S. Shionoya, T. Koda, and R. Hioki, J. Phys. Chem. Solids 29, 935 (1968).

    CAS  Google Scholar 

  70. Y. Imanaka and N. Miura, Phys. Rev. B 50, 14065 (1994).

    Article  CAS  Google Scholar 

  71. P. Lawaetz, Phys. Rev. B 4, 3460 (1971).

    Article  Google Scholar 

  72. See, T. Dietl, H. Ohno, and F. Matsukura, Phys. Rev. B 63, 195205 (2001).

    Article  Google Scholar 

  73. P. Lawaetz, Phys. Rev. B 4, 3460 (1971).

    Article  Google Scholar 

  74. See, T. Dietl, H. Ohno, and F. Matsukura, Phys. Rev. B 63, 195205 (2001).

    Article  Google Scholar 

  75. M. Cardona, J. Phys. Chem. Solids 24, 1543 (1963).

    CAS  Google Scholar 

  76. P. Lawaetz, Phys. Rev. B 4, 3460 (1971).

    Article  Google Scholar 

  77. Obtained from the Luttinger’s parameter [see, T. Dietl, H. Ohno, and F. Matsukura, Phys. Rev. B 63, 195205 (2001)] (mSO=1/γ1).

    Article  Google Scholar 

  78. J. H. Lee and G. Myers, Phys. Status Solidi B 77, K81 (1976).

    Google Scholar 

  79. A. Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984).

    CAS  Google Scholar 

  80. C. G. Van de Walle, Phys. Rev. B 39, 1871 (1989).

    Google Scholar 

  81. D. Bertho, D. Boiron, A. Simon, C. Jouanin, and C. Priester, Phys. Rev. B 44, 6118 (1991).

    Article  CAS  Google Scholar 

  82. D. L. Rode, Phys. Rev. B 2, 4036 (1970).

    Google Scholar 

  83. D. L. Rode, in Semiconductors and Semimetals, edited by R. K. Willardson and A. C. Beer (Academic, New York, 1975), Vol. 10, p. 1.

    Google Scholar 

  84. A. Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984).

    CAS  Google Scholar 

  85. C. G. Van de Walle, Phys. Rev. B 39, 1871 (1989).

    Google Scholar 

  86. D. Bertho, D. Boiron, A. Simon, C. Jouanin, and C. Priester, Phys. Rev. B 44, 6118 (1991).

    Article  CAS  Google Scholar 

  87. A. Qteish and R. J. Needs, Phys. Rev. B 45, 1317 (1992).

    CAS  Google Scholar 

  88. M. Silver, W. Batty, A. Ghiti, and E. P. O’Reilly, Phys. Rev. B 46, 6781 (1992).

    Article  Google Scholar 

  89. T. Nakayama, Solid-State Electron. 37, 1077 (1994).

    Article  CAS  Google Scholar 

  90. R. Said, A. Qteish, and N. Meskini, J. Phys.: Condens. Matter 10, 8703 (1998).

    Article  CAS  Google Scholar 

  91. R. A. Casali and N. E. Christensen, Solid State Commun. 108, 793 (1998).

    Article  CAS  Google Scholar 

  92. A. Gavini and M. Cardona, Phys. Rev. B 1, 672 (1970).

    Article  Google Scholar 

  93. D. W. Langer, R. N. Euwema, K. Era, and T. Koda, Phys. Rev. B 2, 4005 (1970).

    Google Scholar 

  94. G. L. Bir, G. E. Pikus, L. G. Suslina, and D. L. Fedorov, Sov. Phys.-Solid State 12, 926 (1970).

    Google Scholar 

  95. K. B. Ozanyan, L. May, J. E. Nicholls, J. H. C. Hogg, W. E. Hagston, B. Lunn, and D. E. Ashenford, Solid State Commun. 97, 345 (1996).

    Article  CAS  Google Scholar 

  96. A. G. Areshkin, L. I. Vasiljeva, D. L. Fedorov, and L. S. Markov, J. Opt. Soc. Am. B 15, 41 (1998).

    CAS  Google Scholar 

  97. K. Ichino, K. Ueyama, H. Kariya, N. Suzuki, M. Kitagawa, and H. Kobayashi, Appl. Phys. Lett. 74, 3486 (1999).

    Article  CAS  Google Scholar 

  98. A. Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984).

    CAS  Google Scholar 

  99. J. E. Bernard and A. Zunger, Phys. Rev. B 36, 3199 (1987).

    Article  CAS  Google Scholar 

  100. C. G. Van de Walle, Phys. Rev. B 39, 1871 (1989).

    Google Scholar 

  101. D. Bertho, D. Boiron, A. Simon, C. Jouanin, and C. Priester, Phys. Rev. B 44, 6118 (1991).

    Article  CAS  Google Scholar 

  102. T. Nakayama, Solid-State Electron. 37, 1077 (1994).

    Article  CAS  Google Scholar 

  103. S.-H. Wei and A. Zunger, Phys. Rev. B 60, 5404 (1999).

    CAS  Google Scholar 

  104. R. Said, A. Qteish, and N. Meskini, J. Phys.: Condens. Matter 10, 8703 (1998).

    Article  CAS  Google Scholar 

  105. D. W. Langer, R. N. Euwema, K. Era, and T. Koda, Phys. Rev. B 2, 4005 (1970).

    Google Scholar 

  106. S. Ves, U. Schwarz, N. E. Christensen, K. Syassen, and M. Cardona, Phys. Rev. B 42, 9113 (1990).

    Article  CAS  Google Scholar 

  107. See, A. Mang, K. Reimann, St. Rübenacke, and M. Steube, Phys. Rev. B 53, 16283 (1996).

    Article  CAS  Google Scholar 

  108. K. B. Ozanyan, L. May, J. E. Nicholls, J. H. C. Hogg, W. E. Hagston, B. Lunn, and D. E. Ashenford, Solid State Commun. 97, 345 (1996).

    Article  CAS  Google Scholar 

  109. K. Ichino, K. Ueyama, H. Kariya, N. Suzuki, M. Kitagawa, and H. Kobayashi, Appl. Phys. Lett. 74, 3486 (1999).

    Article  CAS  Google Scholar 

  110. A. Blacha, H. Presting, and M. Cardona, Phys. Status Solidi B 126, 11 (1984).

    CAS  Google Scholar 

  111. L. Brey, N. E. Christensen, and M. Cardona, Phys. Rev. B 36, 2638 (1987).

    Article  CAS  Google Scholar 

  112. R. A. Casali and N. E. Christensen, Solid State Commun. 108, 793 (1998).

    Article  CAS  Google Scholar 

  113. R.-Z. Wang, S.-H. Ke, and M.-C. Huang, J. Phys.: Condens. Matter 4, 6735 (1992).

    Google Scholar 

  114. R. L. Schmidt and M. Cardona, in Int. Conf. Phys. Semicond., edited by F. G. Fumi (Tipografia Marves, Rome, 1976), p. 239.

    Google Scholar 

  115. J. M. Calleja, H. Vogt, and M. Cardona, Phil. Mag. 35, 239 (1982).

    Google Scholar 

  116. R.-Z. Wang, S.-H. Ke, and M.-C. Huang, J. Phys.: Condens. Matter 4, 6735 (1992).

    Google Scholar 

  117. Calculated [D. Olguín, M. Cardona, and A. Cantarero, Solid State Commun. 122, 575 (2002)].

    Google Scholar 

  118. K. Brennan, J. Appl. Phys. 64, 4024 (1988).

    Article  CAS  Google Scholar 

  119. D. Berlincourt, H. Jaffe, and L. R. Shiozawa, Phys. Rev. 129, 1009 (1963).

    Article  CAS  Google Scholar 

  120. A. Manabe, A. Mitsuishi, and H. Yoshinaga, Jpn. J. Appl. Phys. 6, 593 (1967).

    Article  CAS  Google Scholar 

  121. T. Hattori, Y. Homma, A. Mitsuishi, and M. Tacke, Opt. Commun. 7, 229 (1973).

    Article  CAS  Google Scholar 

  122. G. A. Samara, Phys. Rev. B 27, 3494 (1983).

    Article  CAS  Google Scholar 

  123. G. A. Samara, Phys. Rev. B 27, 3494 (1983).

    Article  CAS  Google Scholar 

  124. A. Manabe, A. Mitsuishi, and H. Yoshinaga, Jpn. J. Appl. Phys. 6, 593 (1967).

    Article  CAS  Google Scholar 

  125. T. Taguchi, T. Yokogawa, and H. Yamashita, Solid State Commun. 49, 55 (1984).

    Google Scholar 

  126. A. Mang, K. Reimann, St. Rübenacke, and M. Steube, Phys. Rev. B 53, 16283 (1996).

    Article  CAS  Google Scholar 

  127. M. Fernández, P. Prete, N. Lovergine, A. M. Mancini, R. Cingolani, L. Vasanelli, and M. R. Perrone, Phys. Rev. B 55, 7660 (1997).

    Article  Google Scholar 

  128. R. Pässler, E. Griebl, H. Riepl, G. Lautner, S. Bauer, H. Preis, W. Gebhardt, B. Buda, D. J. As, D. Schikora, K. Lischka, K. Papagelis, and S. Ves, J. Appl. Phys. 86, 4403 (1999).

    Google Scholar 

  129. See, M. Julier, J. Campo, B. Gil, J. P. Lascaray, and S. Nakamura, Phys. Rev. B 57, R6791 (1998); D. W. Langer, R. N. Euwema, K. Era, and T. Koda, Phys. Rev. B 2, 4005 (1970).

    Article  CAS  Google Scholar 

  130. A. Mang, K. Reimann, St. Rübenacke, and M. Steube, Phys. Rev. B 53, 16283 (1996).

    Article  CAS  Google Scholar 

  131. See, S. Adachi, Optical Constants of Crystalline and Amorphous Semiconductors: Numerical Data and Graphical Information (Kluwer Academic, Boston, 1999).

    Google Scholar 

  132. See, S. Adachi, Optical Properties of Crystalline and Amorphous Semiconductors: Materials and Fundamental Properties (Kluwer Academic, Boston, 1999).

    Google Scholar 

  133. L. Baldassarre, A. Gingolani, M. Ferrara, and M. Lugarà, Solid State Commun. 34, 237 (1980).

    CAS  Google Scholar 

  134. S. Namba, J. Opt. Soc. Am. 31, 76 (1961).

    Google Scholar 

  135. See, I. P. Kaminow and E. H. Turner, in Handbook of Lasers, edited by R. J. Pressley (Chemical Rubber, Cleveland, 1971), Chap. 15.

    Google Scholar 

  136. T. G. Okroashvili, Opt. Spectrosc. 47, 442 (1979).

    Google Scholar 

  137. H. P. Wagner, M. Kühnelt, W. Langbein, and J. M. Hvam, Phys. Rev. B 58, 10494 (1998).

    Article  CAS  Google Scholar 

  138. C. K. N. Patel, Phys. Rev. Lett. 16, 613 (1966).

    CAS  Google Scholar 

  139. W. Y. Ching and M.-Z. Huang, Phys. Rev. B 47, 9479 (1993).

    Article  CAS  Google Scholar 

  140. E. W. Van Stryland, H. Vanherzeele, M. A. Woodall, M. J. Soileau, A. L. Smirl, S. Guha, and T. F. Boggess, Opt. Eng. 24, 613 (1985).

    Google Scholar 

  141. T. D. Krauss and F. W. Wise, Appl. Phys. Lett. 65, 1739 (1994).

    Article  CAS  Google Scholar 

  142. S. Fujita, H. Mimoto and H. Takebe, and T. Noguchi, J. Cryst. Growth 47, 326 (1979).

    Article  CAS  Google Scholar 

  143. S. Narita and K. Nagasaka, J. Phys. Soc. Jpn 20, 1728 (1965).

    CAS  Google Scholar 

  144. L. C. Olsen, R. C. Bohara, and D. L. Barton, Appl. Phys. Lett. 34, 528 (1979).

    CAS  Google Scholar 

  145. S. Kishimoto, T. Hasegawa, H. Kinto, O. Matsumoto, and S. Iida, J. Cryst. Growth 214/215, 556 (2000).

    Article  CAS  Google Scholar 

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(2004). Cubic Zinc Sulphide (β-ZnS). In: Handbook on Physical Properties of Semiconductors. Springer, Boston, MA. https://doi.org/10.1007/1-4020-7821-8_7

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