We report the growth of ZnO horizontal (NRs) on p-Si substrate at low temperature without any assisting mechanism. The NRs were grown at 90°C on a ZnO film previously deposited using metal-organic chemical vapor deposition. The horizontal nanowires have diameters in the range of 200 – 500nm and lengths between 1 – 7 µm, depending upon the duration of the growth and the ratio of the precursors. The density of the NRs was controlled by varying the concentration of zinc nitrate (Zn(NO3)2) while keeping hexamethylenetetramine (HMTA) constant. Density of horizontal NRs increased with lower zinc nitrate concentration (from 11.35 to 3.29 mMol) for a growth duration of 18hrs. Increased zinc nitrate concentration of 3.29mMol resulted in an asymmetric growth along the vertical axis due to oxygen termination giving rise to slower growth rates.
In this paper, a novel approach for marking integrated circuit packages with authentication nanosignatures is introduced. In this work, the signatures patterns are fabricated using electron beam lithography. Moreover, the robustness of these signatures against aging and humidity is investigated. A recipe comprising image processing techniques and measurement of similarity indices has been developed. These signatures are proposed to be fabricated at the manufacturer side of the supply chain. Then, they are decoded at the consumer end. Thus, robustness against ambient environment and aging is a requirement for these signatures to survive in the global supply chain. Calculated Mean Square Error and Structural SIMilarity Index confirmed that the reflected patterns of the signatures remain unchanged against aging and humidity.
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