Trade-Off for Better Balanced Nonlinear Optical Performance with Disordered Si in ZnGeP₂

Abstract

ZnGeP 2 (ZGP) possesses prominent mid-far infrared nonlinear optical (NLO) performance but suffers from a narrow bandgap. A comparative analysis revealed that the bandgap could be enhanced by substituting Si for Ge in ZGP, successfully synthesizing a series of ZnSi x Ge 1−x P 2 crystals with enlarged bandgaps compared with that of ZGP. Interestingly, when the x varies from 0 to 0.5, in addition to obtaining improved bandgaps, the second-harmonic generation (SHG) responses are enhanced simultaneously, which is abnormal because they are usually inversely proportional. Theoretical calculations with special quasirandom structures show that the NLO coefficient decreases gradually with increasing Si content, but the decrease is tiny in the 0−50% range and acute in the 50−100% range of Si. The transmission experiment of the ZnSi 0.25 Ge 0.75 P 2 wafer indicates that the introduction of silicon effectively improves the transmittance in the 1−2 μm range. The enhanced transmittance and maintained NLO coefficients result in a better macroscopic SHG response. Combined with an increased laser-induced damage threshold, the introduction of Si becomes a practical approach to improve performance and extend the application of ZGP crystals.

Thermoelectric Properties of the Chalcopyrite Solid Solutions ZnGe1–xSnxP2

“…Chalcopyrite materials have been studied for technological applications since the middle of the 20th century with applications in nonlinear optics including ZnGeP 2 , − AgGaSe 2 , and others, photovoltaics, and LEDs, as summarized in a review in 2016 . Chalcopyrite compounds crystallize in the tetragonal I 4̅2 d space group with a charge balanced stoichiometry ABX 2 , where A and B are cations and X are anions (Figure ).…”

Synthesis and Transport Properties of ZnSnP2-yAsy Chalcopyrite Solid Solutions

“…The 2022 NIST Inorganic Crystal Structure Database lists 17 pnictides (A = Mg, Zn, and Cd; B = Si, Ge, and Sn; Pn = P, As, and Sb) and 26 chalcogenides (A = Li, Cu, and Ag; B = Fe, B, Al, Ga, In, and Tl; Q = S, Se, and Te) adopting the chalcopyrite type. For several decades, chalcopyrites have been studied for a number of different applications [1], including ZnGeP 2 [2][3][4], AgGaSe 2 [5] and others [6] as nonlinear optical materials, photovoltaics [7], LEDs [8] and thermoelectric materials [9,10].…”

Salt-inclusion sulfides [K4Cl][MII11In9S26] (MII = Zn, Cd) displaying robust nonlinear optical activity

“…In order to address this issue, extensive efforts have been made to create and develop various IR NLO crystals in different systems, including chalcogenides, oxides, oxychalcogenides, halides, and pnictides. [12][13][14][15][16][17][18][19] Among these systems, metal chalcogenides have emerged as promising NLO materials due to their diverse structures and appealing functional flexibility. According to the anionic group theory, the ''NLO-active functional motif'' has played a crucial role in being responsible for significant SHG responses, 20 such as the distorted tetrahedral [GaS 4 ] in BaGa 4 S 7 21 and LiGaS 2 , 22 trigonal planar [HgSe 3 ] in BaHgSe 2 , 23 and polyhedral [SbS n ] (n = 3, 5) in KSb 5 S 8 .…”