Porous silicon films passivated with graphene aiming at non circular supercapacitors

This work presents the obtainment of porous silicon films by a continuous etch at a constant current density (j = 150 mA/cm
²
, tetch = 180 s) and a stop-etch method employing j = 150 mA/cm
²
for ton = 2 s and j = 0 mA/cm
²
for toff = 10 s. It was noteworthy that both methods produced films with the same gravimetric porosity (76%) although the thicknesses were different (17.7 and 24.3μm, respectively). This is directly correlated with pore size distribution. In order to passivate the porous silicon films, a graphene deposition was performed by means of catalytic growth in a rapid thermal processing (RTP) oven using a mixture of gases (acetylene, hydrogen and argon at 10:200:2000 SCCM, respectively) and a temporal profile of temperature with two steps at 750
^o
C during 10min followed by another one at 850
^o
C during 10min. As a result, graphene passivation for porous silicon was successful achieved. Also, it was inferred from the SEM images that graphene coated all the interstices of the pores so that the corrosion in alkaline solution no longer occurs.