Materials design and development of new spinel silicon nitrides

具有尖晶石结构的立方氮化硅是由一个德国小组于1999年发现的。用第一性原理计算发现，立方氮化硅的直接禁带宽度为3.5 eV，这与传统的六方结构氮化硅的间接带隙和宽禁带有明显的不同。在本研究中，我们结合第一性原理计算和高压实验的努力，为新型尖晶石氮化物的材料设计和开发提供了新的思路。通过系统的理论计算，我们找到了n型和p型半导体氮化物的良好掺杂。对Si-Al-Mg-O-N系中的高压相进行了系统的冲击波合成实验研究。

Cubic silicon nitride having spinel structure was discovered by a German group in 1999. We have found by first principles calculations that the cubic silicon nitride has a direct band gap of 3.5eV, which is markedly different from the indirect and wider band gaps in conventional silicon nitrides with hexagonal structures. It was also predicted to possess higher hardness than hexagonal crystals.In the present study, we have combined efforts of first principles calculations and high pressure experiments to have new ideas for materials design and development of new spinel nitrides.We have found good dopants for n and p-type semiconducting nitrides through systematic theoretical calculations. Shock wave syntheses experiments were systematically made to explore the high pressure phases within Si-Al-Mg-O-N systems.