Band structure engineering in strain-free GaAs mesoscopic systems

Author(s)

Gordo, Vanessa Orsi ^[1] ; Rodrigues, Leonarde N. ^{[2, 3]} ; Knopper, Floris ^{[3, 4]} ; Garcia Jr, Ailton J. ; Iikawa, Fernando ^[5] ; Couto Jr, Odilon D. D. ; Deneke, Christoph ^[6]

Affiliation

^[1] Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[2] Univ Fed Vicosa, Dept Fis, BR-36570000 Vicosa, MG - Brazil

^[3] Lab Nacl Nanotecnol LNNano CNPEM, BR-13083100 Campinas - Brazil

^[4] Eindhoven Univ Technol TUe, Dept Appl Phys, Photon & Semicond Nanophys, POB 513, NL-5600 MB Eindhoven - Netherlands

^[5] Garcia Jr, Jr., Ailton J., Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

^[6] Couto Jr, Jr., Odilon D. D., Garcia Jr, Jr., Ailton J., Univ Estadual Campinas, Inst Fis Gleb Wataghin, BR-13083859 Campinas, SP - Brazil

• Document type: Journal article
• Source: Nanotechnology; v. 31, n. 25 APR 3 2020.
• Web of Science Citations: 0

Abstract

We investigate the optical properties of strain-free mesoscopic GaAs/AlxGa1 - xAs structures (MGS) coupled to thin GaAs/AlxGa1 - xAs 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. (AU)

• FAPESP's process: 16/16365-6 - Nanostructures of III-V semiconductors and their optical properties
• Grantee: Fernando Iikawa
• Support Opportunities: Regular Research Grants
• FAPESP's process: 16/14001-7 - Growth and fabrication of semiconductor nanomembrane structures for basic research and potential device applications
• Grantee: Christoph Friedrich Deneke
• Support Opportunities: Regular Research Grants
• FAPESP's process: 12/11382-9 - Optical modulation of semiconductor nanostructures using surface acoustic waves
• Grantee: Odilon Divino Damasceno Couto Júnior
• Support Opportunities: Research Grants - Young Investigators Grants