Electro-optic Coefficient Enhancement of AlxGa1鈥?i>xN via Multiple Field Modulations

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• 作者：Wei Jiang ; Yaping Wu ; Wei Lin ; Shuping Li ; Junyong Kang
• 刊名：ACS Applied Materials & Interfaces
• 出版年：2015
• 出版时间：August 19, 2015
• 年：2015
• 卷：7
• 期：32
• 页码：17707-17712
• 全文大小：359K
• ISSN：1944-8252

文摘

AlGaN has attracted growing interest for applications in electro-optic devices that generate and process optical signals. To enhance the electric-optic effect with polarity, we designed and grew GaN/Al_xGa_1-xN quantum structures with x of about 0.5 by metal鈥搊rganic vapor-phase epitaxy. Spectroscopic ellipsometry measurement and ab initio calculation demonstrated that the stronger polarization fields induced by higher Al contents in the barrier result in larger electro-optic effects. By applying external biases directly on both sides of these quantum structures, a high intensity of external field was achieved, and extraordinary and ordinary refractive indices were characterized by fitting the variable-angle spectroscopic ellipsometry. The values of deduced electric-optic coefficients were significantly enhanced by combining the resonance effect with the internal and external fields. Given the comparable electric-optic coefficients with conventional electro-optic crystals, AlGaN is an attractive candidate for nonlinear optical material, which provides a basis for large-scale integrations of ultraviolet electro-optic devices based on nitride semiconductors.