Abstract-Manufacturing and terahertz wave modulation properties of graphene/Y3Fe5O12/Si hybrid nanostructures

• Dainan Zhang, 
• Lichuan Jin,  
• Tianlong Wen, 
• Yulong Liao, 
• Qiye Wen, 
• Huaiwu Zhang, 
• Qinghui Yang

• ^a Department of Electrical and Computer Engineering, University of Delaware, Newark, Delaware, 19716, USA
• ^b State Key Laboratory of Electronic Films and Integrated Devices, University of Electronic Science and Technology of China, Chengdu, 610054, China

http://www.sciencedirect.com/science/article/pii/S1359836816319539

In this paper, graphene/Bi:YIG(50 nm)/p-Si hybrid nanostructured graphene field effect transistors (GFETs) were fabricated at the first time. A 50 nm Bi-doped Y₃Fe₅O₁₂ (Bi: YIG) garnet film was deposited using a vacuum RF sputtering technique, forming a nanometer thick high-K gate layer. With reduced Coulomb impurity scattering and cavity effect, a significantly improved modulation depth of 15% and modulation speed of 200 kHz have been successfully achieved with the YIG based GFETs. Moreover, since YIG is a magnetic insulator, we characterized and discussed the possibility of magnetic control of these graphene/Bi:YIG/p-Si hybrid structured THz modulators. A 7% enhancement of THz transmittance with applying an in-plane 22 Oe magnetic field has been revealed in the hybrid nanostructure, which provides a new route to realize electrical/magnetic functional modulators. The results show that graphene/Y₃Fe₅O₁₂/Si hybrid nanostructures with good THz modulation performances have great potential for THz nondestructive evaluation as well as imaging applications.