Grzanka Ewa, Bauer Sondes, Lachowski Artur, Grzanka Szymon, Czernecki Robert, So Byeongchan, Baumbach Tilo, Leszczyński Mike
Institute of High Pressure Physics, Polish Academy of Sciences, Sokolowska 29/37, 01-142 Warsaw, Poland.
TopGaN Ltd., Solec 24/90, 00-403 Warsaw, Poland.
Nanomaterials (Basel). 2025 Jan 17;15(2):140. doi: 10.3390/nano15020140.
In situ X-ray reciprocal space mapping was performed during the interval heating and cooling of InGaN/GaN quantum wells (QWs) grown via metal-organic vapor phase epitaxy (MOVPE). Our detailed in situ X-ray analysis enabled us to track changes in the peak intensities and radial and angular broadenings of the reflection. By simulating the radial diffraction profiles recorded during the thermal cycle treatment, we demonstrate the presence of indium concentration distributions (ICDs) in the different QWs of the heterostructure (1. QW, bottom, 2. QW, middle, and 3. QW, upper). During the heating process, we found that the homogenization of the QWs occurred in the temperature range of 850 °C to 920 °C, manifesting in a reduction in ICDs in the QWs. Furthermore, there is a critical temperature ( = 940 °C) at which the mean value of the indium concentration starts to decrease below 15% in 1. QW, indicating the initiation of decomposition in 1. QW. Moreover, further heating up to 1000 °C results in extended diffuse scattering along the angular direction of the diffraction spot, confirming the propagation of the decomposition and the formation of trapezoidal objects, which contain voids and amorphous materials (In-Ga). Heating InGaN QWs up to = 1000 °C led to a simultaneous decrease in the indium content and ICDs. During the cooling phase, there was no significant variation in the indium concentrations in the different QWs but rather an increase in the defect area, which contributes to the amplification of diffuse scattering. A comparison of ex situ complementary high-resolution transmission microscopy (Ex-HRTEM) measurements performed at room temperature before and after the thermal cycle treatment provides proof of the formation of four different types of defects in the QWs, which result from the decomposition of 1. QW during the heating phase. This, in turn, has strongly influenced the intensity of the photoluminescence emission spectra without any detectable shift in the emission wavelength λ.
通过金属有机气相外延（MOVPE）生长的InGaN/GaN量子阱（QW）在间歇加热和冷却过程中进行了原位X射线倒易空间映射。我们详细的原位X射线分析使我们能够追踪反射峰强度以及径向和角向展宽的变化。通过模拟热循环处理过程中记录的径向衍射轮廓，我们证明了异质结构不同量子阱（1. 量子阱，底部；2. 量子阱，中间；3. 量子阱，上部）中铟浓度分布（ICD）的存在。在加热过程中，我们发现量子阱在850℃至920℃的温度范围内发生了均匀化，表现为量子阱中ICD的减少。此外，存在一个临界温度（ = 940℃），在该温度下，1. 量子阱中铟浓度的平均值开始降至15%以下，表明1. 量子阱开始分解。此外，进一步加热至1000℃会导致沿衍射斑点角向的扩展漫散射，证实了分解的传播以及梯形物体的形成，这些物体包含空隙和非晶材料（In-Ga）。将InGaN量子阱加热至 = 1000℃导致铟含量和ICD同时降低。在冷却阶段，不同量子阱中的铟浓度没有显著变化，而是缺陷面积增加，这导致了漫散射的放大。热循环处理前后在室温下进行的非原位互补高分辨率透射显微镜（Ex-HRTEM）测量的比较证明了量子阱中形成了四种不同类型的缺陷，这些缺陷是由加热阶段1. 量子阱的分解引起的。这反过来又强烈影响了光致发光发射光谱的强度，而发射波长λ没有任何可检测到的偏移。
