Second-Harmonic Generation and Crystal Structure of the Diamond-like Semiconductors Li2CdGeS4 and Li2CdSnS4

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• 作者：Jonathan W. Lekse ; Meghann A. Moreau ; Katie L. McNerny ; Jeongho Yeon ; P. Shiv Halasyamani ; Jennifer A. Aitken
• 刊名：Inorganic Chemistry
• 出版年：2009
• 出版时间：August 17, 2009
• 年：2009
• 卷：48
• 期：16
• 页码：7516-7518
• 全文大小：693K
• 年卷期：v.48,no.16(August 17, 2009)
• ISSN：1520-510X

文摘

The semiconductors Li₂CdGeS₄ and Li₂CdSnS₄, which are of interest for their nonlinear optical properties, were synthesized using high-temperature solid-state and polychalcogenide flux syntheses. Both compounds were found to crystallize in Pmn2₁, with R1 (for all data) = 1.93% and 1.86% for Li₂CdGeS₄ and Li₂CdSnS₄, respectively. The structures of both compounds are diamond-like with the tetrahedra pointing in the same direction along the c axis. The alignment of the tetrahedra results in the structure lacking an inversion center, a prerequisite for second-harmonic generation (SHG). A modified Kurtz nonlinear optical powder technique was used to determine the SHG responses of both compounds. Li₂CdGeS₄ displayed a type I phase-matchable response of approximately 70× α-quartz, while Li₂CdSnS₄ displayed a type I non-phase-matchable response of approximately 100× α-quartz. Diffuse-reflectance spectroscopy was used to determine band gaps of 3.10 and 3.26 eV for Li₂CdGeS₄ and Li₂CdSnS₄, respectively.