Effective mass of InN epilayers

We report on the study of plasma edge absorption of InN epilayers with free electron concentration ranging from 3.5×1017to5×1019cm−3. Together with the previously reported data, the wide range variation of effective mass cannot be explained by Kane’s two band k∙p model alone. We show that the combination of Kane’s two band k∙p model, band renormalized effect due to electron–electron interaction, and electron–ionized impurity interaction can provide an excellent description. The effective mass of the free electron at the bottom of the conduction band was found to be m*=0.05m0, which is in good agreement with the very recent theoretical calculation.