A drift-held in the base region of a solar cell can enhance the effective minority-carrier diffusion length, thus increasing the long-wavelength spectral response and energy-conversion efficiency. Silicon thin-films of 20-32 mu m thickness as a cell base layer were grown by liquid-phase epitaxy (LPE) on electronically inactive heavily doped p(++)-type CZ silicon substrates. Growth was performed from In/Ga solutions, and in a purified Ar/4%H-2 forming gas ambient, rather than pure H-2. The Ga dopant concentration was tailored throughout the p-type film to create a drift-held in the base layer of the solar cell. An independently confirmed efficiency of 16.4% was achieved on such an LPE drift-field thin-him silicon solar cell with a total cell area of 4.11 cm(2). Substrate thinning, combined with light trapping which is encouraged by the textured front surface and a highly reflective aluminium rear surface, is demonstrated to improve the long-wavelength response and thus, increase cell efficiency by a factor of up to 23.7% when thinned to a total cell thickness of 30 mu m.