Queensland Micro- and Nanotechnology Centre, Griffith University, Brisbane 4111, Australia.
Group of Materials and Structures, School of Mechanical Engineering, Hanoi University of Science and Technolog, Hanoi 100000, Vietnam.
ACS Appl Mater Interfaces. 2023 Jun 14;15(23):28781-28789. doi: 10.1021/acsami.3c03045. Epub 2023 May 30.
This paper presents a novel self-powered mechanical sensing based on the vertical piezo-optoelectronic coupling in a 3C-SiC/Si heterojunction. The vertical piezo-optoelectronic coupling refers to the change of photogenerated voltage across the 3C-SiC/Si heterojunction upon application of mechanical stress or strain. The effect is elucidated under different photoexcitation conditions and under varying tensile and compressive strains. Experimental results show that the relationship between the vertical photovoltage and applied strain is highly linear, increasing under the tensile strain while decreasing under the compressive strain. The highest sensitivities to tensile and compressive strains are 0.146 and 0.058 μV/ppm/μW, respectively, which are about 220 and 360 times larger than those of the lateral piezo-optoelectronic coupling reported in literatures. These extremely large changes in vertical photovoltages are explained by the alteration in effective mass, energy band shift, and repopulation of photogenerated holes in out-of-plane, in-plane longitudinal, and in-plane transverse directions when strains are exerted on the heterojunction. The significant enhancement of strain sensitivity will pave the way for development of ultrasensitive and self-powered mechanical sensors based on the proposed vertical piezo-optoelectronic coupling.
本文提出了一种基于 3C-SiC/Si 异质结中垂直压光电耦合的新型自供电机械传感。垂直压光电耦合是指在施加机械应力或应变时，3C-SiC/Si 异质结上光生电压的变化。在不同的光激发条件下和不同的拉伸和压缩应变下，阐明了这种效应。实验结果表明，垂直光电压与施加应变之间的关系具有高度的线性，拉伸应变下增加，压缩应变下减小。对拉伸应变和压缩应变的最高灵敏度分别为 0.146 和 0.058 μV/ppm/μW，分别比文献中报道的横向压光电耦合的灵敏度大 220 倍和 360 倍。当应变施加到异质结上时，在垂直方向上，有效质量、能带位移和光生空穴的再分布发生变化，导致垂直光电压发生显著变化，从而解释了这些巨大的垂直光电压变化。这种应变灵敏度的显著增强将为基于所提出的垂直压光电耦合的超灵敏自供电机械传感器的发展铺平道路。
