{"id":261,"date":"2020-03-19T19:01:24","date_gmt":"2020-03-19T19:01:24","guid":{"rendered":"https:\/\/sites.ifi.unicamp.br\/lpcm\/?p=261"},"modified":"2020-04-06T17:33:12","modified_gmt":"2020-04-06T17:33:12","slug":"new-article-by-group-member-band-structure-engineering-in-strain-free-gaas-mesoscopic-structures","status":"publish","type":"post","link":"https:\/\/sites.ifi.unicamp.br\/lpcm\/2020\/03\/19\/new-article-by-group-member-band-structure-engineering-in-strain-free-gaas-mesoscopic-structures\/","title":{"rendered":"New article by group member: Band structure engineering in strain-free GaAs mesoscopic structures"},"content":{"rendered":"

\"\"<\/a>We investigate the optical properties of strain-free mesoscopic GaAs\/Al(x)Ga(1-x)As structures (MGS) coupled to thin GaAs\/A(x)Ga(1-x)As quantum wells (QWs) with varying Al content (x). We demonstrate that quenching the QW emission by controlling the band crossover between AlGaAs X-point and GaAs Gamma-point gives rise to long carrier lifetimes and enhanced optical emission from the MGS. For x = 0.33, QW and MGS show typical type-I band alignment with strong QW photoluminescence emission and much weaker sharp recombination lines from the MGS localized exciton states. For x >= 0.50, the QW emission is considerably quenched due to the change from type-I to type-II structure while the MGS emission is enhanced due to carrier injection from the QW. For x >= 0.70, we observe PL quenching from the MGS higher energy states also due to the crossover of X and Gamma bands, demonstrating spectral filtering of the MGS emission. Time-resolved measurements reveal two recombination processes in the MGS emission dynamics. The fast component depends mainly on the X-Gamma mixing of the MGS states and can be increased from 0.3 to 2.5~ns by changing the Al content. The slower component, however, depends on the X-Gamma mixing of the QW states and is associated to the carrier injection rate from the QW reservoir into the MGS structure. In this way, the independent tuning of X-Gamma mixing in QW and MGS states allows us to manipulate recombination rates in the MGS as well as to make carrier injection and light extraction more efficient.<\/p>\n

Vanessa Ors Gordo, Leonarde Nascimento Rodrigues, Floris Knopper, Ailton J Garcia, Fernando Iikawa, Odilon D. D. Couto Jr. and Christoph Deneke<\/p>\n

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Nanotechnology 31, 255202 (2020)<\/div>\n<\/div>\n
DOI: 10.1088\/1361-6528\/ab7d74<\/a><\/div>\n
 <\/div>\n<\/div>\n

<\/p>\n","protected":false},"excerpt":{"rendered":"

We investigate the optical properties of strain-free mesoscopic GaAs\/Al(x)Ga(1-x)As structures (MGS) coupled to thin GaAs\/A(x)Ga(1-x)As quantum wells (QWs) with varying Al content (x). We demonstrate that quenching the QW emission by controlling the band crossover between AlGaAs X-point and GaAs Gamma-point gives rise to long carrier lifetimes and enhanced optical emission from the MGS. For … <\/p>\n

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