LITHOGRAPHY-FREE GROWTH OF SILICON MICROWIRES VIA ATMOSPHERIC PRESSURE CHEMICAL VAPOR DEPOSITION FOR OPTOELECTRONIC APPLICATIONS

Realizing the next-generation electronic devices with added features, i.e., flexibility, smaller dimension,
higher density (transistors per unit area), lightweight, and low-power consumption would require extensive
work to optimize the processing conditions that would yield high-quality Si wires (microwire/nanowire)
with optimum device performance at an affordable price. To this end, we employed a cost-effective
lithography-free de-wetting technique to fabricate the seed layer for the growth of highly ordered Si
microwires (Si MWs). A quantitative analysis of the impact of various growth parameters on Si MW size
has been reported. This has important implications since the optoelectronic properties of a wire
configuration are strongly dependent on its size and the quality of the as-grown wires, thereby affecting the
device performance. An exponential dependence of MW growth rate has been reported, and the rate-
limiting step has been determined. The electrical transport properties of as-grown Si MWs have been
extracted via two-probe and three-probe measurements. Temperature-dependent IV measurements have
been done to determine the trap state density and trap energy level in the as-grown and passivated Si MWs.
Lastly, we demonstrate an easily constructed, single wire near-infrared (NIR) photodetector device with an
enhancement observed in responsivity, detectivity, and % EQE of low-powered Si MW by a factor of 44.8,
6.8, and 46.7 at the lowest applied voltage.