Browsing by Author "Baek J.H."

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Open Access
Controlled growth and characterization of epitaxially-laterally-overgrown InGaN/GaN quantum heterostructures
(IEEE, 2010) Sarı, Emre; Akyuz, Özgün; Choi, E. -G.; Lee I.-H.; Baek J.H.; Demir, Hilmi Volkan
Crystal material quality is fundamentally important for optoelectronic devices including laser diodes and light emitting diodes. To this end epitaxial lateral overgrowth (ELO) has proven to be a powerful technique for reducing dislocation density in GaN and its alloys [1,2]. Implementation and design of ELO process is, however, critical for obtaining high-quality material with high-efficiency quantum structures for light emitters [3]. ©2010 IEEE.
Open Access
Investigation of excitonic effects in polar InGaN/GaN quantum heterostructures for enhanced quantum electroabsorption in blue
(IEEE, 2007) Sarı, Emre; Nizamoğlu, Sedat; Özel, Tuncay; Koç, Aslı; Lee I.-H.; Baek J.H.; Demir, Hilmi Volkan
Open Access
Polar vs. nonpolar InGaN/GaN quantum heterostructures: Opposite quantum confined electroabsorption and carrier dynamics behavior
(IEEE, 2010) Sarı, Emre; Nizamoğlu, Sedat; Choi J.H.; Lee, S.J.; Baik, K.H.; Lee I.H.; Baek J.H.; Hwang, S.-M.; Demir, Hilmi Volkan
We present a study of quantum confined electroabsorption and carrier dynamics in polar c-plane and nonpolar a-plane InGaN/GaN quantum heterostructures. We demonstrate red-shifting absorption edge, due to quantum confined Stark effect, in nonpolar InGaN/GaN quantum structures in response to increased electric field, while we show the opposite effect with blue-shifting absorption spectra in polar quantum structures. Moreover, confirmed by time-resolved photoluminescence measurements, we prove that carrier lifetimes increase with increasing electric field for nonpolar structures, whereas the opposite occurs for polar ones.