- and -A2Hg3M2S<
详细信息 查看全文
- 作者：J.-H. Liao ; G. M. Marking ; K. F. Hsu ; Y. Matsushita ; M. D. Ewbank ; R. Borwick ; P. Cunningham ; M. J. Rosker ; and M. G. Kanatzidis
- 刊名：Journal of the American Chemical Society
- 出版年：2003
- 出版时间：August 6, 2003
- 年：2003
- 卷：125
- 期：31
- 页码：9484 - 9493
- 全文大小：353K
- 年卷期：v.125,no.31(August 6, 2003)
- ISSN：1520-5126
文摘
The closely related phases 
- and 
-A2Hg3M2S8 (A = K, Rb; M = Ge, Sn) have been discoveredusing the alkali polychalcogenide flux method and are described in detail. They present new structuretypes with a polar noncentrosymmetric crystallographic motif and strong nonlinear second-harmonicgeneration (SHG) properties. The -allotropic form crystallizes in the orthorhombic space group Aba2 witha = 19.082(2) Å, b = 9.551(1) Å, c = 8.2871(8) Å for the K2Hg3Ge2S8 analogue, and a = 19.563(2) Å, b= 9.853(1) Å, c = 8.467(1) Å for the K2Hg3Sn2S8 analogue. The -form crystallizes in the monoclinic spacegroup C2 with a = 9.5948(7) Å, b = 8.3608(6) Å, c = 9.6638(7) Å, = 94.637
for the K2Hg3Ge2S8 analogue.The thermal stability and optical and spectroscopic properties of these compounds are reported along withdetailed solubility and crystal growth studies of the -
2Hg3Ge2S8 in K2S8 flux. These materials are widegap semiconductors with band gaps at ~2.40 and ~ 2.64 eV for the Sn and Ge analogues, respectively.Below the band gap the materials exhibit a very wide transmission range to electromagnetic radiation upto ~14 
m. -K2Hg3Ge2S8 shows anisotropic thermal expansion coefficients. SHG measurements, performedwith a direct phase-matched method, showed very high nonlinear coefficient deff for -K2Hg3Ge2S8approaching 20 pm/V. Crystals of K2Hg3Ge2S8 are robust to air exposure and have a high laser-damagethreshold.
- and -A2Hg3M2S8 (A = K, Rb; M = Ge, Sn) have been discoveredusing the alkali polychalcogenide flux method and are described in detail. They present new structuretypes with a polar noncentrosymmetric crystallographic motif and strong nonlinear second-harmonicgeneration (SHG) properties. The -allotropic form crystallizes in the orthorhombic space group Aba2 witha = 19.082(2) Å, b = 9.551(1) Å, c = 8.2871(8) Å for the K2Hg3Ge2S8 analogue, and a = 19.563(2) Å, b= 9.853(1) Å, c = 8.467(1) Å for the K2Hg3Sn2S8 analogue. The -form crystallizes in the monoclinic spacegroup C2 with a = 9.5948(7) Å, b = 8.3608(6) Å, c = 9.6638(7) Å, = 94.637 for the K2Hg3Ge2S8 analogue.The thermal stability and optical and spectroscopic properties of these compounds are reported along withdetailed solubility and crystal growth studies of the -2Hg3Ge2S8 in K2S8 flux. These materials are widegap semiconductors with band gaps at ~2.40 and ~ 2.64 eV for the Sn and Ge analogues, respectively.Below the band gap the materials exhibit a very wide transmission range to electromagnetic radiation upto ~14 m. -K2Hg3Ge2S8 shows anisotropic thermal expansion coefficients. SHG measurements, performedwith a direct phase-matched method, showed very high nonlinear coefficient deff for -K2Hg3Ge2S8approaching 20 pm/V. Crystals of K2Hg3Ge2S8 are robust to air exposure and have a high laser-damagethreshold.