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High Resolution Image Download MS PowerPoint Slide Semiconductors with one-dimensional (1D) substructures are promising for next-generation optical and electronic devices due to their directional transport and flexibility. Representatives of this class include HgPbP 14 -type materials. This study investigates the related semiconductors Ag 1.7(1) Ge 1.0(1) P 14 and Ag 1.4(1) Sn 1.0(1) P 14 . Single-crystal X-ray diffraction indicates that their structure is unconventional due to its incommensurate modulation. Both compounds crystallize orthorhombically in the (3 + 1)D superspace group Pnma (0 β 0) s 00 (No. 62.1.9.4). Ag 1.7(1) Ge 1.0(1) P 14 (refined composition Ag 2.2(1) Ge 1.3(1) P 18.7(1) ) with the cell parameters a = 12.986(1) Å, b = 3.2648(4) Å, c = 10.841(1) Å, and a modulation wave vector q = (0, 0.39(1), 0), and Ag 1.4(1) Sn 1.0(1) P 14 (refined as Ag 1.9(1) Sn 1.3(1) P 18.7(1) ) with a = 13.014(1) Å, b = 3.2602(4) Å, c = 10.905(1) Å, and q = (0, 0.42(1), 0) were investigated. Three structural models were generated, differing in modulation functions, site occupancies, and the split of one atomic position. Depending on the occupancy, the structure can be derived from Cu 2 P 20, AgP 15, or HgPbP 14 -type materials. 119 Sn Mössbauer spectroscopy confirms the +II oxidation state of tin in Ag 1.4(1) Sn 1.0(1) P 14 . Additional characterization was performed by scanning electron microscopy with energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, angle-dependent Raman spectroscopy, and photoluminescence measurements. Single-crystal conductivity measurements revealed semiconducting behavior of Ag 1.7(1) Ge 1.0(1) P 14 (0.2 S/cm).
Vosseler et al. (Wed,) studied this question.