The InGaN and InAlN alloys with band gap energy in the range 0.65-6.2 eV have attracted a lot of attention for a variety of heterostructures providing great freedom in choosing device structures for the desired device operation. This paper reports the MOVPE growth of InAlN and InGaN alloys and their heterostructures with an intermediate In content (In: 0.4-0.6). InAlN films of In content of 0.59-1 have been successfully obtained without phase separation, In droplet formation and adduct formation. The adduct formation has been investigated through the parasitic reaction of TMA, TMI and NH3. On the basis of these results, successful MOVPE growth of InAlN/InGaN heterostructure with the suppression of metallic In droplets formation on the surface has been obtained. On the other hand, In droplets were observed on the surface of InGaN/InAlN heterostructure due to the deterioration of InAlN film during the growth of InGaN. These results give important indications toward the fabrication of future devices using InAlN/InGaN heterostructures like LEDs, LDs and solar cells. (C) 2010 Elsevier B.V. All rights reserved.