Schmidt Constance, Rahaman Mahfujur, Zahn Dietrich R T
Semiconductor Physics, Chemnitz University of Technology, D-09107 Chemnitz, Germany.
Nanotechnology. 2021 Nov 2;33(4). doi: 10.1088/1361-6528/ac2f5d.
We demonstrate the conversion to quasi two-dimensional (2D)-GaOby thermally oxidizing layered GaSe of different thicknesses (from bilayer to 100 nm). GaSe flakes were prepared by mechanical exfoliation onto Si with a 300 nm SiOlayer, highly oriented pyrolytic graphite, and mica substrates. The flakes were then annealed in ambient atmosphere at different temperatures ranging from 600 °C to 1000 °C for 30 min. Raman spectroscopy confirmed the formation of-GaOin the annealed samples by comparison with the Raman spectrum of a-GaOreference crystal. Atomic force microscopy was employed to study the morphology and the thickness of the-GaOflakes. In addition, we used energy dispersive x-ray spectroscopy together with scanning electron microscopy to investigate the evolution of the composition, especially Se residuals, and the sample topography with annealing temperature.-GaOappears at temperatures above 600 °C and Se is completely evaporated at temperatures higher than 700 °C. The thicknesses of the resulting-GaOflakes are half of that of the initial GaSe flake. Here we therefore present a straightforward way to prepare 2D-GaOby annealing 2D GaSe.
我们通过对不同厚度（从双层到100纳米）的层状GaSe进行热氧化，展示了向准二维(2D)-GaO的转变。通过机械剥离将GaSe薄片制备在具有300纳米SiO层的Si、高度取向的热解石墨和云母衬底上。然后将薄片在600℃至1000℃的不同温度下在环境气氛中退火30分钟。通过与α-GaO参考晶体的拉曼光谱比较，拉曼光谱证实了退火样品中形成了β-GaO。利用原子力显微镜研究了β-GaO薄片的形态和厚度。此外，我们使用能量色散X射线光谱结合扫描电子显微镜来研究成分的演变，特别是硒残余物，以及退火温度对样品形貌的影响。β-GaO在600℃以上的温度下出现，硒在高于700℃的温度下完全蒸发。所得β-GaO薄片的厚度是初始GaSe薄片厚度的一半。因此，我们在此提出一种通过对二维GaSe进行退火来制备二维β-GaO的直接方法。
