College of Physics and Electrical Information Engineering, Zhejiang Normal University, Jinhua 321017, China.
Institute of Microengineering and Nanoelectronics, Universiti Kebangsaan Malaysia, Bangi 43600, Selangor, Malaysia.
Sensors (Basel). 2023 Feb 23;23(5):2464. doi: 10.3390/s23052464.
Gallium nitride (GaN), widely known as a wide bandgap semiconductor material, has been mostly employed in high power devices, light emitting diodes (LED), and optoelectronic applications. However, it could be exploited differently due to its piezoelectric properties, such as its higher SAW velocity and strong electromechanical coupling. In this study, we investigated the affect of the presence of a guiding layer made from titanium/gold on the surface acoustic wave propagation of the GaN/sapphire substrate. By fixing the minimum thickness of the guiding layer at 200 nm, we could observe a slight frequency shift compared to the sample without a guiding layer, with the presence of different types of surface mode waves (Rayleigh and Sezawa). This thin guiding layer could be efficient in transforming the propagation modes, acting as a sensing layer for the binding of biomolecules to the gold layer, and influencing the output signal in terms of frequency or velocity. The proposed GaN/sapphire device integrated with a guiding layer could possibly be used as a biosensor and in wireless telecommunication applications.
氮化镓（GaN），作为一种广为人知的宽带隙半导体材料，主要应用于高功率器件、发光二极管（LED）和光电应用中。然而，由于其压电特性，如较高的表面声波（SAW）速度和较强的机电耦合，它可以被以不同的方式加以利用。在这项研究中，我们研究了钛/金导向层的存在对 GaN/蓝宝石衬底表面声波传播的影响。通过将导向层的最小厚度固定在 200nm，我们可以观察到与没有导向层的样品相比，存在不同类型的表面模式波（瑞利和表面声子波）时，频率会发生轻微的偏移。这种薄的导向层可以有效地改变传播模式，作为金层与生物分子结合的传感层，并在频率或速度方面影响输出信号。与导向层集成的 GaN/蓝宝石器件可作为生物传感器和无线电信应用。
