Wuhan National Laboratory for Optoelectronics (WNLO) and School of Physics, Huazhong University of Science and Technology, Wuhan 430074, People's Republic of China.
Nanotechnology. 2019 Jul 26;30(30):305201. doi: 10.1088/1361-6528/ab1739. Epub 2019 Apr 8.
In this work, we present an experimental study on the acoustic vibrations of ZnO nanoparticles array with different concentration of Ga dopings by using femtosecond pump-probe technique. The Ga-doped ZnO (GZO) nano-triangle particles with the sizes of 190, 232 and 348 nm are fabricated by nanosphere lithography and pulsed laser deposition method. The result indicates that the frequency of acoustic vibrations of GZO nanoparticles decrease as the Ga-concentration is increased. Importantly, the vibration period of the GZO nanoparticles at the same Ga doping concentration show a nonlinear increase as the nanoparticle size is increased, which is different from the common linear dependency in undoped ZnO nanoparticles. It may be attributed to the crystal structure distortion and elastic characteristics variation due to Ga doping, and the elastic modulus at 7.3% Ga doping is decreased by 30%-60% for GZO nanoparticles with different sizes. The study can be very helpful for evaluating the crystal structure distortion and elastic characteristics of doped nano-materials with optical methods. Besides, it can offer a complementary method of thermal management in ZnO based optoelectronic devices.
在这项工作中，我们通过飞秒泵浦探测技术研究了不同 Ga 掺杂浓度的 ZnO 纳米粒子阵列的声振动。采用纳米球光刻和脉冲激光沉积法制备了尺寸为 190、232 和 348nm 的 Ga 掺杂 ZnO（GZO）纳米三角颗粒。结果表明，随着 Ga 浓度的增加，GZO 纳米颗粒的声振动频率降低。重要的是，在相同 Ga 掺杂浓度下，GZO 纳米颗粒的振动周期随着纳米颗粒尺寸的增加呈非线性增加，这与未掺杂 ZnO 纳米颗粒的常见线性依赖关系不同。这可能归因于 Ga 掺杂引起的晶体结构畸变和弹性特性变化，以及不同尺寸的 GZO 纳米颗粒的弹性模量在 7.3%Ga 掺杂时降低了 30%-60%。这项研究对于通过光学方法评估掺杂纳米材料的晶体结构畸变和弹性特性非常有帮助。此外，它还可以为基于 ZnO 的光电设备的热管理提供一种补充方法。
