Characterisation of InGaN by Photoconductive Atomic Force Microscopy
Department of Materials Science & Metallurgy, University of Cambridge, 27 Charles Babbage Road, Cambridge CB3 0FS, UK
*
Author to whom correspondence should be addressed.
Materials 2018, 11(10), 1794; https://doi.org/10.3390/ma11101794
Received: 5 July 2018 / Revised: 29 August 2018 / Accepted: 3 September 2018 / Published: 21 September 2018
(This article belongs to the Special Issue III-Nitrides Semiconductor Research in the UK and Ireland)
Nanoscale structure has a large effect on the optoelectronic properties of InGaN, a material vital for energy saving technologies such as light emitting diodes. Photoconductive atomic force microscopy (PC-AFM) provides a new way to investigate this effect. In this study, PC-AFM was used to characterise four thick (∼130 nm) In Ga N films with x = 5%, 9%, 12%, and 15%. Lower photocurrent was observed on elevated ridges around defects (such as V-pits) in the films with %. Current-voltage curve analysis using the PC-AFM setup showed that this was due to a higher turn-on voltage on these ridges compared to surrounding material. To further understand this phenomenon, V-pit cross sections from the 9% and 15% films were characterised using transmission electron microscopy in combination with energy dispersive X-ray spectroscopy. This identified a subsurface indium-deficient region surrounding the V-pit in the lower indium content film, which was not present in the 15% sample. Although this cannot directly explain the impact of ridges on turn-on voltage, it is likely to be related. Overall, the data presented here demonstrate the potential of PC-AFM in the field of III-nitride semiconductors.
View Full-Text
Keywords:
InGaN; photoconductive atomic force microscopy; dislocations
▼
Show Figures
This is an open access article distributed under the Creative Commons Attribution License which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited
MDPI and ACS Style
Weatherley, T.F.K.; Massabuau, F.C.-P.; Kappers, M.J.; Oliver, R.A. Characterisation of InGaN by Photoconductive Atomic Force Microscopy. Materials 2018, 11, 1794. https://doi.org/10.3390/ma11101794
AMA Style
Weatherley TFK, Massabuau FC-P, Kappers MJ, Oliver RA. Characterisation of InGaN by Photoconductive Atomic Force Microscopy. Materials. 2018; 11(10):1794. https://doi.org/10.3390/ma11101794
Chicago/Turabian StyleWeatherley, Thomas F.K.; Massabuau, Fabien C.-P.; Kappers, Menno J.; Oliver, Rachel A. 2018. "Characterisation of InGaN by Photoconductive Atomic Force Microscopy" Materials 11, no. 10: 1794. https://doi.org/10.3390/ma11101794
Find Other Styles
Note that from the first issue of 2016, MDPI journals use article numbers instead of page numbers. See further details here.
Search more from Scilit