Optimization of organized silicon nanowires growth inside porous anodic alumina template using hot wire chemical vapor deposition process

A Hot Wire assisted Chemical Vapor Deposition (HWCVD) process has been developed for producing high-density arrays of parallel, straight and organized silicon nanowires (SiNWs) inside vertical Porous Anodic Alumina (PAA) templates, exploring temperatures ranging from 430 °C to 600 °C, and pressures varying between 2.5 and 7.5 mbar. In order to prevent parasitic amorphous silicon (a-Si) deposit and to promote the crystalline SiNWs growth, we used a tungsten hot wire to partially crack H2 into atomic hydrogen, which acts like a selective etchant regarding a-Si. Here we describe the optimization route we followed to limit the deposit of a-Si onto the surface of the porous membrane and on the walls of the pores, which led to the possibility to grow SiNWs inside the PAA membranes. Such an approach has high potentialities for device realization, like PIN junctions, FETs or electrodes for Li-ion batteries.