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Cataloged from PDF version of article.A redshift of the peak emission wavelength was observed in the blue light emitting diodes of InGaN/GaN grown with a higher temperature interlayer that was sandwiched between the low-temperature buffer layer and high-temperature unintentionally doped GaN layer. The effect of interlayer growth temperature on the emission wavelength was probed and studied by optical, structural, and electrical properties. Numerical studies on the effect of indium composition and quantum confinement Stark effect were also carried out to verify the experimental data. The results suggest that the redshift of the peak emission wavelength is originated from the enhanced indium incorporation, which results from the reduced strain during the growth of quantum wells. (C) 2012 American Institute of Physics. [http://dx.doi.org/10.1063/1.3694054

In this study, the growth and properties of LiAlO2 material and a nonpolar GaN-based light-emitting-diode (LED) structure on LiAlO2 have been investigated. The LiAlO2 material is grown by the Czochralski pulling technique and is used as a substrate for nonpolar nitride growth. An improved surface roughness can be obtained by a four-step polishing process. With subsequent nitridation treatment, a pure M-plane (101̱0) GaN can be obtained. An electron microscope shows an abundance of cracks that are oriented parallel to the (001) and (100) planes of the LiAlO2 substrate on the rear surface of GaN. The absence of the polarization-induced electric field of a GaN-based LED structure on LiAlO2 was shown by using photoluminescence measurements. Therefore, this approach is promising to further increase the luminescence performance of GaN-based LEDs.

.55. Jk, 81.15.Gh Wurtzite GaN is usually used for optoelectronic devices. Because of the growth along the polar c-axis, the strong piezoelectric and spontaneous polarizations fields result in a band bending which is responsible for the poor electron-hole overlap in quantum well structures. The growth along the m-plane direction is one possibility to deposit non-polar material and leads to efficient recombination across the entire well of the QW structure. LiAlO 2 (LAO) offers the advantage to grow GaN along the m-plane direction. This work provides the results from investigations on the deposition of GaN-based structures on LAO substrates by metal-organic chemical vapor deposition.1 Introduction There is huge interest worldwide at present in finding an alternative substrate for the GaN-based epitaxial deposition. Currently, silicon carbide (SiC) and sapphire are the most favorite wafers for the AlGaInN material system. These substrates suffer from the limitations that growth is only possible along the polar c-axis which leads to strong piezoelectric and spontaneous polarization fields. The band bending related to polarization-induced fields is responsible for the poor electron-hole overlap. To achieve highly efficient quantum well (QW) structures, growth along non-polar axes is required. The m-plane growth direction demonstrates one of the non-polar axes for the deposition of the nitrides, prevents the band bending and provides direct recombination across the whole well. LiAlO 2 (LAO) substrates, with their huge advantage of low cost and easy substrate removal, offer the possibility to grow GaN along the m-plane direction. The growth of GaN on this substrate has been investigated by several research groups [1][2][3][4][5][6][7][8][9][10][11]. This work provides the results from investigations on the deposition of GaN-based structures on LAO substrates.

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