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We report here the effect of a controlled modification of the shell microstructure around the crystalline core of a silicon nanowire (SiNW) grown at a low (320 °C) temperature by the hot wire chemical vapor processing (HWCVP) method. We demonstrate these effects through the evaluation of the performance of a micro-supercapacitor (µ-SC) device fabricated with these SiNWs having different shell structures. It is to be emphasized that the shell microstructure could be modified through a controlled interplay of the process parameters during the growth. A careful optimization of the shell microstructure in these nanowires during its low-temperature deposition has led to a µ-SC with capacitance value of 94 µF/cm. This result opens up exciting opportunities for HWCVP-grown SiNWs to be employed for on-chip µ-SC and other low-temperature applications. [ABSTRACT FROM AUTHOR]

In this work, the effect of chamber pressure on the morphology of hot wire chemical vapor processed silicon nanowires (SiNWs) using Sn as catalyst has been studied. It is observed that their geometrical orientation can be controlled as per requirement by adjusting the growth pressure. SiNWs synthesized at low pressure of 0.67 Pa grow preferentially perpendicular to the substrate. If the pressure is increased to 2.7 Pa, SiNWs become tilted to the substrate and have bending type structure with random distribution. Further increase in the chamber pressure to 4 Pa very few wires are seen to grow and at 5.3 Pa no-growth of SiNWs is observed. Transmission electron microscopy study shows that the straight SiNWs have crystalline structure whereas the bent ones show polycrystalline structure. [ABSTRACT FROM AUTHOR]