Influence of hydrogen input partial pressure on the polarity of InN on GaAs (1 1 1)A grown by metalorganic vapor phase epitaxy

Influences of hydrogen input partial pressure in the carrier gas (Fo=PH2o/(PH2o+PN2o)) on the crystalline quality and polarities of InN on GaAs (1 1 1)A surfaces were investigated by metalorganic vapor phase epitaxy (MOVPE). It was found that the polarity of the InN was affected by the hydrogen gas in the system regardless of the polarity of GaAs starting substrate. The polarity of InN layer grown with the hydrogen partial pressure of Fo=0.004 was a mixture of In-polarity and N-polarity, while that grown with Fo=0 was In-polarity. Degradation of the crystalline quality of InN grown with Fo=0.004 occurred due to the polarity inversion during the growth. The reason why the polarity of InN was influenced by the hydrogen carrier gas could be explained by the preferential growth of N-polarity InN in the H2 contained ambient and/or the limiting reaction of InN decomposition.