LiGaGe₂S₆: A Chalcogenide with Good Infrared Nonlinear Optical Performance and Low Melting Point

Abstract

In this work, we design and synthesize a new chalcogenide LiGaGeS on the basis of known infrared (IR) material LiGaS by partially substituting Ga with Ge. This compound possesses very strong nonlinear (NLO) response (2.5 × LiGaS) and large band gap (3.52 eV), manifesting a better balance between band gap and NLO response compared with that for LiGaS. Moreover, LiGaGeS exhibits a much lower melting point (663 °C) than that of LiGaS (1050 °C). This would result in the much smaller vapor pressure of sulfur in the fused quartz vessels used for the crystal growth, and thus, it should be greatly beneficial to obtain the large stoichiometric LiGaGeS single crystal. Our studies demonstrate that LiGaGeS is a good candidate material for IR NLO applications.

Synthesis, structural and spectroscopic properties of orthorhombic compounds BaLnCuS3 (Ln = Pr, Sm)

“…Complex chalcogenide compounds have interesting chemical and physical properties and the materials are widely used in modern optical and electronic technologies [1][2][3][4][5][6][7][8][9][10]. In recent years, complex Cu + -containing sulfides and selenides were considered as promising thin film absorber materials in solar cell structures [11][12][13][14][15][16].…”

Layered and Cubic Semiconductors AGaM′Q4 (A+ = K+, Rb+, Cs+, Tl+; M′4+ = Ge4+, Sn4+; Q2– = S2–, Se2–) and High Third-Harmonic Generation

“…Examples include the fast ion exchange in KInSn 2 S 6 for the capture of lanthanide ions and the strong nonlinear optical (NLO) second-harmonic generation (SHG) of noncentrosymmetric compounds. Materials like LiGaGe 2 Q 6 , − A 2 In 2 M ′ Q 6 , − and TlGaSn 2 Q 6 − are especially promising NLO candidates. For the compounds with the stoichiometric composition AMM ′ Q 4 ( A = K, Rb, Cs, Tl; M = Al; Ga, In; M ′ = Si; Ge, Sn; Q = S, Se), compounds containing indium and mixtures of gallium and tin have been mostly reported. − Among the respective gallium germanium compounds only KGaGeS 4 has been reported .…”

“…Interestingly, the Cs + cations in this phase are also 9-fold coordinated by the S 2− anions like in CsGaGeS 4 -mP28, and the mean distances d̅ (Ga/Ge−S) are basically identical. The main structural difference between CsGaGaS 4 -aP28 and its monoclinic polymorph is that, in monoclinic CsGaGaS 4 -mP28, the anionic layers are completely (5), CsGaGeS 4 -oP56 (6), and CsGaSnS 4 -oP56 (7), a slight change in the layered structure occurs. Basic crystallographic data for these compounds can be found in Table 1.…”

“…This measurement, however, revealed no additional thermal events aside from the melting point at ∼840 °C. An X-ray powder diffraction analysis following the measurement revealed that the sample had transformed to CsGaGeS 4 -oP56 (5). In order to better understand this transformation, triclinic CsGaGeS 4 -aP28 was investigated using in situ high-temperature X-ray powder diffraction (Figure 3).…”

Li7Cd4.5Ge4Se16 and Li6.4Cd4.8Sn4Se16: Strong Nonlinear Optical Response in Quaternary Diamond‐Like Selenide Networks

“…First-principles calculations based on DFT calculations have provedt hat the introductiono fa lkali or alkaline-earth metalsi ntoI RN LO materials is helpful to increase the bandgap because there are no orbitals located at the very top of valence bands in these compounds compared with Ag-containing ones.F or example, substitution of Ag with Li in the AgGaQ 2 (Q = S, Se) series enlarged the bandgaps of LiGaS 2 and LiGaSe 2 to 4.15 and 3.34 eV,r espectively,w hicha re much larger than those of AgGaS 2 (2.64 eV) and AgGaSe 2 (1.80 eV). [29][30][31][32] Thus, chalcogenidest hat contain alkali or alkaline-earth metals have attracted our attention,p articularly those that contain Li, because the small Li atom will be conducive to dense packing of the NLO-active functional units.…”