Phase transformation and microstructures of Ln2S3 (Ln = La, Sm) with different impurities content of oxygen and carbon

Synthesis of La<SUB>2</SUB>S<SUB>3</SUB> Thin Films by Sulfurization of LaCl<SUB>3</SUB> and CS(NH<SUB>2</SUB>)<SUB>2</SUB>

“…As mentioned above, the oxygen impurity prevents the formation of -La 2 S 3 . 15,17) Moreover, the lanthanum-rich solution promotes the formation of -La 2 S 3 . The reason for the lowtemperature formation of -La 2 S 3 is that titanium and tantalum are also efficient deoxidizers and desulfurizers for the formation of La 2 S 3 thin films.…”

“…15,16) The relationship between the oxygen impurity content and the thermoelectric properties is not entirely understood. While the presence of oxygen stabilizes the tetragonal form over a wide temperature range, the -La 2 S 3 phase with low oxygen content undergoes further transformation into the -La 2 S 3 phase at around 1600 K. 15,17) The -La 2 S 3 phase forms a cubic-defect Th 3 P 4 -type structure over the composition range La 2 S 3 -La 3 S 4 . [12][13][14] In La 2 S 3 (La 2:67 S 4 ), 4/3 sites of the 12 lanthanum sites per unit cell are vacant.…”

Preparation of Sm2S3 thin films by liquid phase deposition method with self-assembled monolayers

“…The reported preparation route for the Sm 2 S 3 consists of the sulfurization of Sm 2 O 3 using CS 2 or H 2 S gas [5][6][7][8][9]. However the Sm 2 S 3 powder prepared using CS 2 gas contains the impurities of oxygen and carbon [7], and the preparation temperature is too high. Conversely, the self-assembled monolayers (SAMs) technique is a new method, which is based on the traditional liquid phase deposition method and bio-mineralization theory.…”

Thermoelectric properties and phase stability of La/sub 10/S/sub 14/O

“…[7,8] The tetragonal lattice constants a and c increase as oxygen content decreases. [7,9] Since the substitutional oxygen has influence on the phase transformation, it is difficult to obtain the high temperature gamma-phase. While the La 10 S 15-x O x with x = 0 (beta-La 2 S 3 ) transforms to the gamma-phase at about 1573 K, the La 10 S 15-…”