We have proposed a novel solution with a use of a (308) 4H-SiC substrate for the reduction of internal polarization in the GaInN QWs. With changing the pressure at the initial stage of the nitride growth, two crystallographic orientations of the nitride layers could be switched. When the growth pressure was as high as 1013 hPa, the c-axis of the GaN is 54.7° tilted from the surface plane. On the other hand, the GaN having 7° tilted c-axis was dominant with the growth pressure of 100 hPa, where there is a relationship of SiC (0001) // GaN (101). We fabricated a LED on the (308) 4H-SiC substrate, where the c-axis orientation of 54.7° is tilted from the surface plane. The blue shift of the peak wavelength with increasing injection current was confirmed to be smaller than that of conventional LED grown along the c-axis on sapphire substrate. This small blue shift may be certain evidence that the GaInN active layer has small internal field as we expected. (© 2005 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)
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Kamiyama et al. (2005) studied this question.