Structural differences in Mg-doped InN - Indication of polytypism

Abstract

Transmission Electron Microscopy shows that the InN samples doped with either increasing or constant Mg concentration follow a cation or anion substrate polarity. In-polar samples change growth polarity when the Mg concentration is >1019 cm-3. N-polar samples have much higher density of planar defects than In-polar samples and their presence leads to a decrease in dislocation density. In the N-polar samples equally spaced planar defects are observed for Mg concentration >1019 cm -3. Three different polytypes (2H, 3C and 4H) were observed in this type of samples. A band of planar defects with thick layers of a cubic material (3C) is observed for Mg concentration >1020 cm-3. At this Mg concentration only n-type conductivity was reported earlier. © 2010 Wiley-VCH Verlag GmbH & Co. KGaA.