Department of Materials Science and Engineering, I-Shou University, Kaohsiung, Taiwan.
Nanotechnology. 2010 Sep 24;21(38):385705. doi: 10.1088/0957-4484/21/38/385705. Epub 2010 Aug 27.
Bright room temperature visible emission is obtained in heterostructures consisting of approximately 3.5 nm thick ZnO ultrathin films grown on Si-nanowires produced by means of self-masking dry etching in hydrogen-containing plasma. The ZnO films were deposited on Si-nanowires by using atomic layer deposition (ALD) under an ambient temperature of 25 degrees C. The orders of magnitude enhancement in the intensity of the room temperature photoluminescence peaked around 560 nm in the present ZnO/Si-nanowire heterostructures is presumably due to the high aspect (surface/volume) ratio inherent to the Si-nanowires, which has, in turn, allowed considerably more ZnO material to be grown on the template and led to markedly more efficient visible emission. Moreover, the ordered nanowire structure also features an extremely low reflectance (approximately 0.15%) at 325 nm, which may further enhance the efficiency of emission by effectively trapping the excitation light.
在由厚度约为 3.5nm 的 ZnO 超薄薄膜和通过含氢等离子体自掩干法刻蚀制作的 Si 纳米线组成的异质结构中，获得了明亮的室温可见发射。在 25°C 的环境温度下，通过原子层沉积（ALD）在 Si 纳米线上沉积了 ZnO 薄膜。本研究中 ZnO/Si 纳米线异质结构中室温光致发光峰值约为 560nm 的强度呈数量级增强，这可能归因于 Si 纳米线固有的高纵横比（表面积/体积），这反过来又允许在模板上生长更多的 ZnO 材料，并导致更有效的可见光发射。此外，有序纳米线结构在 325nm 处还具有极低的反射率（约 0.15%），这可以通过有效捕获激发光进一步提高发射效率。
