We report the subwavelength antireflection structures in various semiconductor materials such as Si, ZnO, and GaP/light emitting diode (LED) structure for LED and solar cell applications in the visible and near-infrared wavelength region, together with the rigorous coupled wave analysis simulation. Subwavelength structures are fabricated by holographic lithography and dry etching, effectively suppressing the surface reflection. To enhance the absorption efficiency over a wide-angle broadband range of incident light, the thin-film crystalline Si solar cells with subwavelength structure, which reduce the surface reflection, are studied. The improvement of light intensity is achieved for the fabricated LEDs with a subwavelength structure compared to the conventional LEDs due to a strongly reduced internal reflection at the semiconductor/air interface.