Ammonothermal Synthesis, Optical Properties, and DFT Calculations of Mg2PN3 and Zn2PN3

Mallmann, Mathias; Maak, Christian; Niklaus, Robin and Schnick, Wolfgang (2018): Ammonothermal Synthesis, Optical Properties, and DFT Calculations of Mg2PN3 and Zn2PN3. In: Chemistry-A European Journal, Vol. 24, No. 52: pp. 13963-13970

Abstract

The phosphorus nitrides, Mg2PN3 and Zn2PN3, are wide band gap semiconductor materials with potential for application in (opto)electronics or photovoltaics. For the first time, both compounds were synthesized ammonothermally in custom-built high-temperature, high-pressure autoclaves starting from P3N5 and the corresponding metals (Mg or Zn). Alkali amides (NaNH2, KNH2) were employed as ammonobasic mineralizers to increase solubility of the starting materials in supercritical ammonia through formation of reactive intermediates. Single crystals of Mg2PN3, with length up to 30m, were synthesized at 1070K and 140MPa. Zn2PN3 already decomposes at these conditions and was obtained as submicron-sized crystallites at 800K and 200MPa. Both compounds crystallize in a wurtzite-type superstructure in orthorhombic space group Cmc2(1), which was confirmed by powder X-ray diffraction. In addition, single-crystal X-ray diffraction measurements of Mg2PN3 were carried out for the first time. To our knowledge, this is the first single-crystal X-ray study of ternary nitrides synthesized by the ammonothermal method. The band gaps of both nitrides were estimated to be 5.0eV for Mg2PN3 and 3.7eV for Zn2PN3 by diffuse reflectance spectroscopy. DFT calculations were carried out to verify the experimental values. Furthermore, a dissolution experiment was conducted to obtain insights into the crystallization behavior of Mg2PN3.

• Item Type: Journal article
• Faculties: Chemistry and Pharmacy > Department of Chemistry
• Subjects: 500 Science > 540 Chemistry
• ISSN: 0947-6539
• Language: English