Resonant Raman scattering and photoluminescence in SiOx/CdSe multiple quantum wells

Nesheva, D; Raptis, C; Levi, Z

dc.contributor.author	Nesheva, D	en
dc.contributor.author	Raptis, C	en
dc.contributor.author	Levi, Z	en
dc.date.accessioned	2014-03-01T01:14:07Z
dc.date.available	2014-03-01T01:14:07Z
dc.date.issued	1998	en
dc.identifier.issn	1098-0121	en
dc.identifier.uri	https://dspace.lib.ntua.gr/xmlui/handle/123456789/12875
dc.subject	Multiple Quantum Well	en
dc.subject	Resonance Raman	en
dc.subject.classification	Physics, Condensed Matter	en
dc.subject.other	SEMICONDUCTOR NANOCRYSTALS	en
dc.subject.other	ELECTRONIC-STRUCTURE	en
dc.subject.other	LATTICE CONTRACTION	en
dc.subject.other	OPTICAL-PROPERTIES	en
dc.subject.other	CDSE FILMS	en
dc.subject.other	SIZE	en
dc.subject.other	THIN	en
dc.subject.other	LUMINESCENCE	en
dc.subject.other	MULTILAYERS	en
dc.subject.other	DOTS	en
dc.title	Resonant Raman scattering and photoluminescence in SiOx/CdSe multiple quantum wells	en
heal.type	journalArticle	en
heal.identifier.primary	10.1103/PhysRevB.58.7913	en
heal.identifier.secondary	http://dx.doi.org/10.1103/PhysRevB.58.7913	en
heal.language	English	en
heal.publicationDate	1998	en
heal.abstract	Raman scattering, photoluminescence, and x-ray diffraction measurements have beer, carried out in SiOx/CdSe multilayers with varying CdSe sublayer thickness d(w) (2.5, 3.5, 4.0, 5.0, and 10.0 nm). The x-ray data have revealed that after annealing at 673 K in air, CdSe wurtzite type nanocrystals are formed having an average size smaller than the CdSe sublayer thickness. A strong increase in the intensity of 1 LO phonon Raman band of CdSe at room temperature has been observed for samples with d(w) 3.5 and 4.0 nm when excited by the 647.1 nm Kr+ laser line. This increase is attributed to resonant conditions for Raman scattering brought about by an increase of the optical band-gap energy E-g of CdSe layers with decreasing sublayer thickness. It is argued that this E-g increase is not ar. internal strain-related, but a quantum-size effect manifested by one-dimensional carrier confinement. Assuming such a confinement and taking into consideration electrical and optical measurements, a band diagram is produced for the SiOx/CdSe system, from which the E-g values for each multilayer material is calculated. It is found that the calculated E-g values corresponding to d(w) = 3.5 and 4.0 nm differ by 59 and 19 meV, respectively, from the quantum energy of the 647.1 nm (1.916 eV) laser line, thus supporting the above arguments and the idea that these structures constitute multiquantum wells. Two photoluminescence bands of CdSe layers have been observed in all multilayers. The peak of the main band shifts from 1.76 to 1.95 eV for multilayers with d(w) from 10 to 2.5 nm. This shift provides further evidence that the E-g increase with decreasing d(w) is due to quantum-size effect. [S0163-1829(98)06836-2].	en
heal.publisher	AMERICAN PHYSICAL SOC	en
heal.journalName	Physical Review B - Condensed Matter and Materials Physics	en
dc.identifier.doi	10.1103/PhysRevB.58.7913	en
dc.identifier.isi	ISI:000076130500066	en
dc.identifier.volume	58	en
dc.identifier.issue	12	en
dc.identifier.spage	7913	en
dc.identifier.epage	7920	en