This paper describes at first the present status of solar cell efficiencies prepared by Hot Wire CVD (HW-CVD), and then preparation techniques of mu c-3C(cubic)-SiC developed for innovative solar cell applications by using HW-CVD method are presented. For preparing mu c-3C-SiC, monomethylsilane (MMS) and hydrogen were used for reactant gases. The high conductivity of 5 S/cm could be achieved for N doped n-type mu c-3C-SiC. For p-type, as-grown Al-doped mu c-3C-SiC films showed a relatively high resistivity, but on thermal annealing, the conductivity increased to the level of 1 x 10(-2) S/cm. Monomethylgermane (MMG) and H, were used to prepare mu c-GeC thin films. mu c-GeC thin films with a carbon composition of about 7-8% showed a clear shift of absorption coefficient spectra by 0.44 eV, when compared to crystalline Ge. The pin solar cell structures in which all p,i,n layers consist of mu c-SiC have been prepared for the first time. It was found that mu c-3C-SiC and mu c-GeC are the promising candidates as the next generation thin-film solar cell materials, but at present, the film quality is strictly limited by the residual impurity concentration of filament material Re. (C) 2007 Elsevier B.V. All rights reserved.