We used Na-flux method to grow Ga-polar GaN (Ga-GaN) and N-polar GaN (N-GaN) on a double-sided epitaxially polished HVPE-GaN seed. The growth behavior and stress distribution of Ga and N-polar GaN grown by Na-flux method was systematically studied for the first time. Under near-thermodynamic equilibrium growth conditions, the growth rate of the N-polar plane is higher than that of the Ga-polar plane, which is related to the high surface energy of the N-polar plane. The lower overall stress level of Ga-GaN/N-GaN bulk single crystals is confirmed by Raman spectroscopy and low-temperature PL. Three-dimensional atom probe tomography (3D-APT) directly proves that C and O impurities are enriched at the atomic level at the growth interface, resulting in the mismatch of the interface lattice, resulting in compressive stress and reduction of free carriers. Under near-thermodynamic equilibrium growth conditions, the dislocation density of GaN bulk single crystals can be further reduced. Ga-GaN and N-GaN dislocation density values were 4 × 10⁵/cm² and 8 × 10⁵/cm², respectively. The mechanism of dislocation reduction is discussed. In addition, we can achieve control of stress and free carriers by adjusting the behavior of impurity incorporation.

我们使用 Na-flux 方法在双面外延抛光的 HVPE-GaN 种子上生长 Ga 极性 GaN (Ga-GaN) 和 N 极性 GaN (N-GaN)。首次系统地研究了Na-flux法生长的Ga和N极性GaN的生长行为和应力分布。在近热力学平衡生长条件下，N极面的生长速率高于Ga极面，这与N极面的高表面能有关。拉曼光谱和低温 PL 证实了 Ga-GaN/N-GaN 块状单晶的整体应力水平较低。三维原子探针断层扫描（3D-APT）直接证明C和O杂质在生长界面原子级富集，导致界面晶格错配，导致压应力和自由载流子减少。在接近热力学平衡生长条件下，GaN块状单晶的位错密度可以进一步降低。Ga-GaN和N-GaN位错密度值为4×10^{分别为 5} /cm ²和 8 × 10 ⁵ /cm ²。讨论了位错减少的机制。此外，我们可以通过调整杂质掺入行为来实现对应力和自由载流子的控制。