Selective-area room temperature visible photoluminescence from SiC/Si heterostructures

Abstract

SiC/Si heterostructures have been patterned by reactive ion etching with CHF3/O2 to produce SiC-covered and Si-exposed regions with lateral dimensions of 2.5 to ∼500 μm. The patterned samples were then anodized in HF/ethanol solutions. Short anodization times (<3 min) result in selective-area UV-induced visible photoluminescence (PL), with a peak located at 650 nm, being observed at 25 °C from only the SiC-covered regions. The emission is generated by porous Si (PoSi) selectively formed under the SiC cap and transmitted through the wide band-gap SiC layer. Longer etching times result in nonselective PL.

Influence of the anodic etching current density on the morphology of the porous SiC layer

“…Furthermore, most studies have fabricated porous SiC using bulk crystalline SiC, while few studies have fabricated porous SiC from thin films. 2,3,[7][8][9][10][11][12][13][14] SiC thin films are easy to make and relatively inexpensive compared with bulk SiC, and we believe that thin films are suitable for most applications. In many applications, the SiC thin film may be amorphous rather than crystalline: for example, researchers have reported using amorphous SiC thin films to fabricate humidity sensors 2 and ammonia sensors.…”

Silicon Nanocrystals in Porous Silicon and Applications

“…The mask must be HF resistant or stable enough to withstand HF during anodization. Standard photoresists can be used but are degraded during anodization leading to undercutting and anodization through the mask via pinholes [32][33][34]. Si dioxide can be used for short anodization times [32,35].…”