State Key Laboratory of Information Photonics and Optical Communications, Beijing University of Posts and Telecommunications, Beijing, 100876, China.
Beijing Computational Science Research Center, Beijing, 100193, China.
Sci Rep. 2017 Sep 6;7(1):10594. doi: 10.1038/s41598-017-11093-4.
A theoretical study of InNBi alloy by using density functional theory is presented. The results show non-linear dependence of the lattice parameters and bulk modulus on Bi composition. The formation energy and thermodynamic stability analysis indicate that the InNBi alloy possesses a stable phase over a wide range of intermediate compositions at a normal growth temperature. The bandgap of InNBi alloy in Wurtzite (WZ) phase closes for Bi composition higher than 1.5625% while that in zinc-blende (ZB) phase decreases significantly at around 356 meV/%Bi. The Bi centered ZB InNBi alloy presents a change from a direct bandgap to an indirect bandgap up to 1.5625% Bi and then an oscillates between indirect bandgap and semi-metallic for 1.5625% to 25% Bi and finally to metallic for higher Bi compositions. For the same Bi composition, its presence in cluster or uniform distribution has a salient effect on band structures and can convert between direct and indirect bandgap or open the bandgap from the metallic gap. These interesting electronic properties enable III-nitride closing the bandgap and make this material a good candidate for future photonic device applications in the mid-infrared to THz energy regime.
采用密度泛函理论对 InNBi 合金进行了理论研究。结果表明，晶格参数和体弹性模量与 Bi 组成呈非线性关系。形成能和热力学稳定性分析表明，在正常生长温度下，InNBi 合金在较宽的中间组成范围内具有稳定的相。在 wurtzite (WZ)相，当 Bi 组成高于 1.5625%时，InNBi 合金的能隙闭合，而在锌矿 (ZB)相，当 Bi 组成约为 356 meV/%Bi 时，能隙显著降低。在 ZB 相，具有中心 Bi 的 InNBi 合金从直接带隙转变为间接带隙，Bi 组成高达 1.5625%，然后在 1.5625%到 25%Bi 之间在间接带隙和半金属之间振荡，最后在更高的 Bi 组成下变为金属。对于相同的 Bi 组成，其在团簇或均匀分布中的存在对能带结构有显著影响，可以在直接带隙和间接带隙之间转换，或者将能带从金属间隙打开。这些有趣的电子特性使 III-氮化物能够关闭带隙，使这种材料成为未来中红外到太赫兹能区光子器件应用的良好候选材料。
