Cathodoluminescence studies of GaN coalesced from nanopyramids selectively grown by MOVPE

Lethy, K J and Edwards, P R and Liu, C and Shields, P A and Allsopp, D W E and Martin, R W (2012) Cathodoluminescence studies of GaN coalesced from nanopyramids selectively grown by MOVPE. Semiconductor Science and Technology, 27 (8). 085010. (https://doi.org/10.1088/0268-1242/27/8/085010)

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Abstract

Coalescence of GaN over arrays of GaN nanopyramids has important device applications and has been achieved on nano-imprint lithographically patterned GaN/sapphire substrates using metal organic vapour phase epitaxy. Spatially and spectrally resolved cathdoluminescence (CL) from such coalesced layers are studied in detail. The observed redshift of the GaN band edge emission with increasing electron beam depth of maximum CL into the coalesced layer is discussed in relation to a carrier-induced peak shift, likely due to Si out-diffusion from the mask material into the GaN. Depth-resolved CL measurements are used to quantify the redshift in terms of bandgap renormalization and strain effects. CL maps showing the GaN near band edge peak energy distribution reveal micron-scale domain-like variations in peak energy and are attributed to the effects of local strain.

ORCID iDs

Lethy, K J, Edwards, P R ORCID logoORCID: https://orcid.org/0000-0001-7671-7698, Liu, C, Shields, P A, Allsopp, D W E and Martin, R W ORCID logoORCID: https://orcid.org/0000-0002-6119-764X;
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