Graduate School of Advanced Technology and Science, Tokushima University, 2-1 Minami-Josanjima, Tokushima, Tokushima, 770-8506, Japan.
Institute of Post-LED Photonics, Tokushima University, 2-1 Minami-Josanjima, Tokushima, Tokushima, 770-8506, Japan.
Sci Rep. 2023 Feb 27;13(1):3308. doi: 10.1038/s41598-023-30489-z.
AlGaN-based ultraviolet (UV) light-emitting diodes (LEDs) are expected to have various applications, including sensing and printing, and light with ultraviolet-C (UVC) wavelengths has a virus inactivation effect. The metalorganic vapor phase epitaxy (MOVPE) method has been used to fabricate LED devices with film control and impurity doping. However, to achieve high luminous efficiency, highly crystalline aluminum nitride (AlN) must be grown in the underlying layer. Although high temperatures are required to grow high-quality AlN for strong migration at the surface, there is a trade-off in the high temperature promoting parasitic reactions. These parasitic reactions are more dominant at a high V/III ratio with more raw material in the case of using the conventional MOVPE. Here, we used jet stream gas flow MOVPE to investigate the effect of V/III ratio dependencies in optimizing AlN growth and without affecting parasitic reaction conditions. As a result, trends of typical AlN crystal growth at V/III-ratio dependencies were obtained. AlN is more stable at a higher V/III ratio of 1000, exhibiting a double atomic step surface, and the crystal orientation is further improved at 1700 °C compared to that at a lower V/III ratio.
基于 AlGaN 的紫外（UV）发光二极管（LED）有望应用于各种领域，包括感测和打印等，而具有紫外-C（UVC）波长的光具有病毒灭活效果。金属有机气相外延（MOVPE）方法已被用于制造具有薄膜控制和杂质掺杂的 LED 器件。然而，为了实现高发光效率，必须在底层生长高结晶性氮化铝（AlN）。尽管为了在表面上实现强迁移而需要高温来生长高质量的 AlN，但高温会带来寄生反应的权衡。在使用传统 MOVPE 的情况下，高 V/III 比会有更多的原料，寄生反应的影响更为显著。在这里，我们使用射流气流 MOVPE 来研究优化 AlN 生长时 V/III 比依赖性的影响，而不影响寄生反应条件。结果，获得了 V/III 比依赖性下典型 AlN 晶体生长的趋势。在更高的 V/III 比为 1000 时，AlN 更为稳定，表现出双原子台阶表面，并且在 1700°C 时的晶体取向比在较低的 V/III 比时进一步改善。
