Pressure dependence of AgInS ₂ crystals grown by hot‐press method

Abstract

AgInS 2 crystal could be grown by a Hot-Press (HP) method with pressure (10 ~ 90 MPa) at 700 ˚C. From X-ray diffraction measurements, the samples grown at 10 ~ 40 MPa were found to contain only AgInS 2 phase. However, a signal from AgIn 5 S 8 phase increased with increasing pressure above 40 MPa. The lattice parameters of a and c axes increased and were almost constants with increasing pressure below and above 40 MPa, respectively. A donor-type defect of interstitial Ag might be enhanced to electrical conductivity in the all samples because samples indicated n-type conductivity examined by thermoprobe analysis. Moreover, high purity sample could be obtained in the HP method because a free exciton emission was clearly and no deep emission was observed in the photoluminescence spectrum.

Photoelectrochemical performances of AgInS2 film electrodes fabricated using the sulfurization of Ag–In metal precursors

“…The optical band gaps of samples can be obtained by plotting (ahn) 1/n with respect to hv and extrapolating the plot to (ahn) 1/n ¼0. It is well known that I-III-VI 2 ternary compounds have direct band gaps [33,34]. The linear dependence of (ahn) 2 on hv is shown in Fig.…”

Glutathione-Capped Quaternary Ag–(In,Ga)–S Quantum Dots Obtained by Colloidal Synthesis in Aqueous Solutions

“…Other atmospheric pressure phases, orthorhombic AgInS 2 (PDF 25-1328) [#48] and cubic spinel-type AgIn 5 S 8 (PDF 25-1329) [50], show the most intense peaks at 28.38 ∘ and 27.32 ∘ , respectively. Under high pressure, tetragonal AgInS 2 either retains tetragonal structure with distortion, or, under pressure and heating, is transformed into spinel (partially starting at 0.04 GPa, 700 ∘ C) [51], rocksalt-type (2.0 GPa, 400 ∘ C) (no powder pattern data) [52] or rhombohedral 𝛼-NaFeO 2 -type structure (4.0 GPa, 50 ∘ C) with the major peak at 33.2 ∘ (PDF 22-1329) [44]. The Ag-(In,Ga)-S QD size for the non-fractioned colloidal solutions estimated from the width of the diffraction maximum using the well-known Scherrer equation is about 2 nm, which correlates with earlier data obtained for Ag-In-S QDs prepared by a similar method [10,11,39,48].…”

Photoluminescence Study of AgInS2 by Using Confocal Microscopy System

“…The samples used for PL measurements were bulk crystals grown by the hot-press method with source composite ratios of Ag/In of 1/1 at 700 C for 1 h under high pressure (25 MPa). 7) The surfaces of the samples were mechanically polished using alumina powder with a particle size of 0.1 m. Each sample was mounted in a continuous flow cryostat (JANIS ST-500), which was cooled by means of liquid helium, and was held at temperatures between 5 and 300 K. A Ti:sapphire laser (Spectra Physics Mai Tai VF-T1S) and a harmonic generator (Spectra Physics GWU23F) were used as excitation sources at a wavelength of 400 nm (3.1 eV in photon energy units). The PL measurement was performed using a scanning confocal microspectroscopy system (Tokyo Instruments Nanofinder 30) and a detector of a charge-coupled device (Tokyo Instruments DV420A-OE).…”