Article comprising a semiconducting material
View Patent ↗Single crystals of the new semiconducting oxychalcogenide phase were synthesized using a novel crystal growth method. The crystals had low defects and homogeneous composition as characterized by single crystal X-ray diffraction and scanning electron microscopy, respectively. Heat capacity and resistivity measurements were in agreement with the calculated band structure calculations indicating semiconductivity, with a band gap of about 3 eV.
1. An oxychalcogenide composition, comprising:
a tetragonal crystalline material, further comprising:
an anionic chalcogen, where the chalcogen is tellurium, selenium, sulfur, a combination of tellurium and a pnictogen, a combination of selenium and a pnictogen, or a combination of sulfur and a pnictogen;
wherein the pnictogen is up to 20 atomic % of the chalcogen anions; oxygen; and
R, where R is an alkaline earth metal cation, where the alkaline earth metal cation is beryllium, magnesium, calcium, strontium, barium, radium, or mixtures thereof;
wherein the molar ratio of the alkaline earth metal cation to the anionic chalcogen is about 2:1.
2. The oxychalcogenide composition of claim 1 , wherein the alkaline earth metal cation is barium.
3. The oxychalcogenide composition of claim 1 , wherein the molar ratio of the alkaline earth metal cation to the anionic chalcogen to the oxygen is about 2:1:1.
4. The oxychalcogenide composition of claim 1 , wherein the composition is Ba 2 TeO.
5. The oxychalcogenide composition of claim 1 , wherein the composition comprises one unit of RX and one unit of RO;
where X is an anionic chalcogen.
6. The oxychalcogenide composition of claim 5 , wherein the composition comprises puckered layers of RO and 2D layers of R-anionic chalcogen alternating along the c-axis.
7. The oxychalcogenide composition of claim 1 , wherein the chalcogen comprises tellurium.
8. The oxychalcogenide composition of claim 1 , wherein the pnictogen is nitrogen, phosphorus, arsenic, antimony, or bismuth.
9. The oxychalcogenide composition of claim 8 , wherein the pnictogen comprises bismuth.
10. An oxychalcogenide composition, comprising:
a tetragonal crystal of repeating units of RX and RO;
wherein R is an alkaline earth metal cation, X is an anionic chalcogen, and O is oxygen;
where the anionic chalcogen is sulfur, selenium, or telluride;
where the alkaline earth metal cation is beryllium, magnesium, calcium, strontium, barium, radium, or mixtures thereof;
where the alkaline earth metal cation of RO is integrated into a crystalline structure with the unit of RX; and
wherein the R:X molar ratio is about 2:1.
11. The oxychalcogenide composition of claim 10 , wherein the composition is Ba 2 TeO.
12. The oxychalcogenide composition of claim 10 , further comprising a unit of RY integrated in the crystalline structure of the oxychalcogenide composition;
where Y is non-chalcogen anion;
wherein the unit of RY replaces a unit of RX in the crystal; and
wherein RY comprises up to 20 atomic percent of RX.
13. The oxychalcogenide composition of claim 12 , wherein the non-chalcogen anion comprises a pnictogen.
14. The oxychalcogenide composition of claim 13 , wherein the pnictogen comprises bismuth.