InAs self-assembled quantum dots (SA-QDs) were incorporated into GaAlAs/GaAs heterostructure for solar cell applications. The structure was fabricated by molecular beam epitaxy on p-GaAs substrate. After the growth of GaAs buffer layer, multi-stacked InAs QDs were grown by self-assembly with a slow growth rate of 0.01 ML/s, which provides high dot quality and large dot size. Then, the structure was capped with n-GaAs and wide band gap n-GaAlAs was introduced. One, two or three stacks of QDs were sandwiched in the p-n heterojunction. The contribution of QDs in solar cell hetero-structure is the quantized nature and a high density of quantized states. I-V characterization was conducted in the dark and under AM1 illumination with 100mW/cm(2) light power density to confirm the solar cell performance. Photocurrent from the QDs was confirmed by spectral response measurement using a filtered light source (1.1-mu m wavelength) and a tungsten halogen lamp with monochromator with standard lock-in technique. These experimental results indicate that QDs could be an effective part of solar cell heterostructure. A typical I-V characteristic of this yet-to-be-optimized solar cell, with an active area of 7.25 mm(2) , shows an open circuit voltage V-OC of 0.7 V, a short circuit current I-SC of 3.7 mA, and a fill factor FF of 0.69, leading to an efficiency eta of 24.6% (active area). (c) 2006 Elsevier B.V. All rights reserved.