X-ray diffraction analysis of cubic zincblende III-nitrides

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Frentrup, M 
Lee, LYL 
Sahonta, S-L 
Kappers, MJ 

Solving the green gap problem is a key challenge for the development of future LED-based light systems. A promising approach to achieve higher LED efficiencies in the green spectral region is the growth of III-nitrides in the cubic zincblende phase. However, the metastability of zincblende GaN along with the crystal growth process often lead to a phase mixture with the wurtzite phase, high mosaicity, high densities of extended defects and point defects, and strain, which can all impair the performance of light emitting devices. X-ray diffraction (XRD) is the main characterization technique to analyze these device-relevant structural properties, as it is very cheap in comparison to other techniques and enables fast feedback times. In this review, we will describe and apply various XRD techniques to identify the phase purity in predominantly zincblende GaN thin films, to analyze their mosaicity, strain state, and wafer curvature. The different techniques will be illustrated on samples grown by metalorganic vapor phase epitaxy on pieces of 4'' SiC/Si wafers. We will discuss possible issues, which may arise during experimentation, and provide a critical view on the common theories.

X-ray diffraction, cubic GaN, phase analysis, Gallium Nitride
Journal Title
Journal of Physics D: Applied Physics
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IOP Publishing
Engineering and Physical Sciences Research Council (EP/M010589/1)
Engineering and Physical Sciences Research Council (EP/N01202X/1)
Technology Strategy Board (TS/N003756/1 - 132135)
Engineering and Physical Sciences Research Council (EP/P03036X/1)
We would like to thank Anvil Semiconductors Ltd. for providing 3C-SiC on Si templates for our experiments, and Innovate UK for financial support within the Energy Catalyst Round 2—Early Stage Feasibility scheme (Ref. 132135): 'To demonstrate the potential to make low cost, high efficiency LEDs using 3C-SiC substrates'. S-L Sahonta and M J Kappers would also like to acknowledge the support of EPSRC through platform grant no. EP/M010589/1: 'Beyond Blue: New Horizons in Nitrides'. D J Wallis would like to acknowledge the support of EPSRC through grant no. EP/N01202X/1.
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