Fabrication of highly dense conical nanostructures and their subsequent controlled metallization make them ideal candidates for enhancing cold cathode electron emission efficiency. For instance, hierarchical growth of self-assembled noble metal nanoparticles on self-organized nanostructured materials offers the advantage of fabricating low threshold cold cathode electron emitters. However, the fabrication of stable Si nanostructure-based cold cathode electron emitters with ultra-low threshold fields is a challenging task. This report presents cold cathode electron emission from Au-NP-decorated ensembles of self-organized silicon nanofacets (Si-NFs) having fascinating ultralow turn-on fields (as low as 0.27 V μm⁻¹) and remarkably low threshold electric fields (as low as 0.37 V μm⁻¹) with outstanding stability. It is interesting to note that even as-prepared Si-NFs offer hitherto unseen low turn-on fields (as low as 0.58 V μm⁻¹) and threshold electric fields (0.66 V μm⁻¹) – so far as silicon-based nanostructures are concerned. Kelvin probe force microscopy studies reveal that tunability in the work function of Au-NP-decorated Si-NF samples depends on the dimension and growth-angle of gold nanoparticles (Au-NPs). In addition, in-depth dual pass tunnelling current microscopy measurements demonstrate that the Au-NPs on the apexes and sidewalls of Si-NFs act as cold cathode electron emission sites which help to improve the turn-on and threshold fields for Au-NP-decorated Si-NFs in comparison to their as-prepared counterparts where electron emission takes place mostly from their sidewalls and valleys. Furthermore, finite element electrostatic field-based simulations reinforce the experimental observations. The present investigation paves the pathway to the fabrication of self-organized Si nanostructure-based highly stable cold cathode electron emitting devices having fascinating low turn-on and threshold fields along with extremely high field enhancement factors and high stability for use in nanoscale electronic devices.