Thick InGaN alloys with high In content are essential for emerging InGaN photovoltaic applications. By applying a compositionally graded structure, various thicknesses of InGaN layers were grown using metal organic chemical vapor deposition. We could obtain pseudomorphic and highly strained layer even upto 100 nm of InGaN film as confirmed by X-ray reciprocal space mapping and Raman spectra. To probe the validity of those InGaN layers for solar cell applications, optical transmittance measurements were carried out and absorption properties were compared. (C) 2013 Elsevier B.V. All rights reserved.