The impact of hydrogen on indium incorporation and surface accumulation in InAlN epitaxy

Introducing a small flow of hydrogen during the metal organic vapour phase epitaxy of InAlN will moderately reduce the indium incorporation into an epilayer while significantly reducing the volume of metallic indium on the surface as droplets, without significantly changing the nanoscale surface structure. Comparison with previous results suggests that this is a better way of removing surface indium while minimising the reduction of incorporated indium than increasing the temperature, and is similarly effective to change the TMI:TMA ratio. These results are consistent with the presence of an indium adlayer on the InAlN surface during growth facilitating indium incorporation.

► H2 was added to the MOVPE growth of InAlN. ► H2 does not reduce In surface mobility, but does reduce bulk In incorporation. ► H2 also significantly reduces the volume of surface indium droplets. ► Comparison with InGaN growth suggests that an In adlayer is needed for InAlN growth.