| Summary: | 碩士 === 國立成功大學 === 微電子工程研究所碩博士班 === 96 === In this study, a simple, fast, low-cost technique for rapidly producing large-area, aligned single-crystalline SiNW arrays on Si wafers by metal-induced etching at near room temperature were demonstrated. The etching technique shows little dependence on the orientation or doping type of the Si wafer. The nanostructure of SiNWs could be modified by appropriate modifying the etching parameter (solution concentration, etching time and temperature) during the etching process. Device application of SiNWs arrays with desirable axial crystallographic orientation and doping characteristics could be readily obtained by using this etching technique. To prepare preparation and characterization of p-type and n-type SiNWs with different metal-induced etching parameters (such as solution concentration, etching time and temperature) were presented. Experimented results revealed that the p-type SiNWs prepared in the solution of AgNO3 and HF is 0.03 molL-1 and 5molL-1, respectively, at 90oC for 60 min have the comparably best field emission characterization with a turn on electric field Eon = 2.25 V/um (@ 10 uA/cm2) and the maximum current density is Jmax = 3.5 mA/cm2 and a field emission factor is B= 4233, which due to the reduction of electric field emission screening effect of the thinner tip and appropriate density of the as-prepared SiNWs. Vertical-aligned Porous silicon nanowires (SiNWs) with a porous-like surface were also prepared in this study by a two-step etching process. Strong orange-red light emission at around 670 nm were observed, which is primarily due to a strong enhancement in quantum confinement effect arising from the nano-scaled porous morphologies of SiNWs. The porous SiNWs also demonstrated better field emission (FE) characteristics as compared to those without porous surface (i.e., non-porous SiNWs). A turn-on field intensity (Eon) of 2.7 V/um, an emission current density up to 1 mA/cm2 at around 5.83 V/um, and an enhancement factor (B) of around 2650 were achieved from SiNWs after subjected to a 3-min etching to form porous surface were found. It is expected that porous SiNWs with the merits of high aspect-ratio and high surface-to-volume ratio could be a potential material for the applications of FE emitters, UV detectors, and solar cells.
|
|---|
