Self-assembled nc-Si-QD/a-SiC thin films from planar ICP-CVD plasma without H2-dilution: a combination of wide optical gap, high conductivity and preferred ⟨220⟩ crystallographic orientation, uniquely appropriate for nc-Si solar cells

Spontaneous miniaturization of self-assembled nc-Si-QDs with preferred < 220 > crystallographic orientation and a rapid synthesis of superior quality nc-Si-QD/a-SiC thin films with enhanced crystallinity, maintaining a combination of wide optical gap and simultaneous high electrical conductivity, has been attained from (SiH4 + CH4)-plasma, without any additional H-2-dilution in inductively coupled plasma CVD. The optical gap widens due to the Si-C bonds in the amorphous network and the increased quantum confinement effect on the miniaturized Si-QDs. CH4 acts as the dual source of both C and atomic-H. High density of atomic-H available in the planar ICP promotes simultaneously the Si crystallization and its growth along the thermodynamically favored < 220 > crystallographic orientation, thereby contributing easier electrical transport, particularly at devices in superstrate configuration. After imminent doping, these could be efficiently utilized as window layers in third generation all-silicon solar cells.