Semibulk InGaN: A novel approach for thick, single phase, epitaxial InGaN layers grown by MOVPE

In this paper we demonstrate a solution to systematically obtain thick, single phase InGaN epilayers by MOVPE. The solution consists in periodically inserting ultra-thin GaN interlayers during InGaN growth. Measurements by HAADF-STEM, X-ray diffraction, cathodoluminescence and photoluminescence demonstrate the effective suppression of the three-dimensional sublayer that is shown to spontaneously form in control InGaN epilayers grown without this method. Simulation predicts that tunneling through the GaN barriers is efficient and that carrier transport through this semi-bulk InGaN/GaN structure is similar to that of bulk InGaN. Such structures may be useful for improving the efficiency of InGaN solar cells by allowing thicker, higher quality InGaN absorption layers.

► The periodic insertion of thin GaN inter-layers during InGaN growth prevents phase separation in InGaN.
► XRD, CL, PL and STEM confirm the suppression of the relaxed top InGaN layer.
► Numerical simulations show that the impact of the thin GaN interlayers on carrier transport in this material is minimal.