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Ultrafast Spectroscopy of Hybrid Ingan/gan Quantum Wells

Description: Group III nitrides are efficient light emitters. The modification of internal optoelectronic properties of these materials due to strain, external or internal electric field are an area of interest. Insertion of metal nanoparticles (MNPs) (Ag, Au etc) inside the V-shaped inverted hexagonal pits (IHP) of InGaN/GaN quantum wells (QWs) offers the potential of improving the light emission efficiencies. We have observed redshift and blueshift due to the Au MNPs and Ag MNPs respectively. This sh… more
Date: August 2012
Creator: Mahat, Meg Bahadur
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Non-free-electron momentum- and thickness-dependent evolution ofquantum well states in the Cu/Co/Cu(001) system

Description: We present systematic k{sub {parallel}}-dependent measurements of the Fermi surface and underlying band structure of quantum well states in Cu/Co/Cu(001). Compared to bands from normal emission, we find a complicated evolution of ''split'' QW states as a function of the thicknesses of both the copper overlayer and the cobalt barrier layer. Self-consistent calculations show that the penetration of the quantum well states into the cobalt barrier layer is significant and leads to the observed very… more
Date: May 21, 2005
Creator: Rotenberg, Eli; Wu, Y. Z.; An, Joonhee M.; Van Hove, Michel A.; Canning, Andrew; Wang, Lin-Wang et al.
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
open access

Linear, Nonlinear Optical and Transport Properties of Quantum Wells Composed of Short Period Strained InAs/GaAs Superlattices

Description: In this work, ordered all-binary short-period strained InAs/GaAs superlattice quantum wells were studied as an alternative to strained ternary alloy InGaAs/GaAs quantum wells. InGaAs quantum wells QWs have been of great interest in recent years due to the great potential applications of these materials in future generations of electronic and optoelectronic devices. The all binary structures are expected to have all the advantages of their ternary counterparts, plus several additional benefits r… more
Date: December 1993
Creator: Huang, Xuren
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Expulsion of Carriers from the Double-Barrier Quantum Well and Investigation of Its Spectral and Transport Consequences

Description: In this work I investigate the expulsion of carriers from nanostructures using the double-barrier quantum well (DBQW) as an example and discuss manifestations of this effect in the spectrum of the DBQW in absence of bias, and in the tunneling current in presence of bias. Assuming equality of the Fermi energy in all regions of the considered system, I compute the relative density of carriers localized in the DBQW and conclude that a fraction of carriers is expelled from this nanostructure.
Date: March 1992
Creator: Chyla, Wojciech Tadeusz
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Interaction of Plasmons and Excitons for Low-Dimension Semiconductors

Description: The effects of surface plasmon for InGaN/GaN multi-quantum wells and ZnO nanoparticles optical linear and nonlinear emission efficiency had been experimentally studied. Due to the critical design for InGaN MQWs with inverted hexagonal pits based on GaN, both contribution of surface plasmon effect and image charge effect at resonant and off resonant frequencies were experimentally and theoretically investigated. With off- resonant condition, the InGaN MQWs emission significantly enhanced by meta… more
Date: December 2014
Creator: Lin, Jie (physicist)
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Field Dependence of Optical Properties in Quantum Well Heterostructures Within the Wentzel, Kramers, and Brillouin Approximation

Description: This dissertation is a theoretical treatment of the electric field dependence of optical properties such as Quantum Confined Stark (QCS) shifts, Photoluminescence Quenching (PLQ), and Excitonic Mixing in quantum well heterostructures. The reduced spatial dimensionality in heterostructures greatly enhances these optical properties, more than in three dimensional semiconductors. Charge presence in the quantum well from doping causes the potential to bend and deviate from the ideal square well pot… more
Date: August 1989
Creator: Wallace, Andrew B.
Item Type: Refine your search to only Thesis or Dissertation
Partner: UNT Libraries
open access

Measurement of the indium segregation in InGaN based LEDs with single atom sensitivity

Description: In light emitting diodes (LED) consisting of GaN/InGaN/GaN quantum wells (QWs), the exact indium distribution inside the wells of the active region affects the performance of devices. Indium segregation can take place forming small InGaN clusters of locally varying composition. In the past, we used a local strain analysis from single HRTEM lattice images to determine the In composition inside the InGaN QWs with a resolution of 0.5 nm x 0.3 nm. Truly atomic resolution can be pursued by exploitat… more
Date: July 30, 2003
Creator: Jinschek, Joerg; Kisielowski, Christian; Van Dyck, Dirk & Geuens, Philippe
Item Type: Refine your search to only Article
Partner: UNT Libraries Government Documents Department
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