Suppression of the quantum-confined Stark effect in AlxGa1-xN/AlyGa1-yN corrugated quantum wells
2013 (English)In: Journal of Applied Physics, ISSN 0021-8979, E-ISSN 1089-7550, Vol. 114, no 12Article in journal (Refereed) Published
We report comparative studies of 6-nm-thick AlxGa1-xN/AlyGa1-yN pyroelectric quantum wells (QWs) grown by plasma-assisted molecular beam epitaxy on c-sapphire substrates with a thick AlN buffer deposited under different growth conditions. The Al-rich growth conditions result in a 2D growth mode and formation of a planar QW, whereas the N-rich conditions lead to a 3D growth mode and formation of a QW corrugated on the size scale of 200-300 nm. Time-resolved photoluminescence (PL) measurements reveal a strong quantum-confined Stark effect in the planar QW, manifested by a long PL lifetime and a red shift of the PL line. In the corrugated QW, the emission line emerges 200 meV higher in energy, the low-temperature PL lifetime is 40 times shorter, and the PL intensity is stronger (similar to 4 times at 4.5K and similar to 60 times at 300 K). The improved emission properties are explained by suppression of the quantum-confined Stark effect due to the reduction of the built-in electric field within the QW planes, which are not normal to the  direction, enhanced carrier localization, and improved efficiency of light extraction.
Place, publisher, year, edition, pages
American Institute of Physics (AIP) , 2013. Vol. 114, no 12
Engineering and Technology
IdentifiersURN: urn:nbn:se:liu:diva-100494DOI: 10.1063/1.4822155ISI: 000325391100056OAI: oai:DiVA.org:liu-100494DiVA: diva2:662930
Funding Agencies|RFBR|12-02-00856-a12-02-00865-a13-02-00801-a13-02-12231-ofi-m|Pesidium of RAS|24|2013-11-082013-11-082015-09-22