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Papers by Vladimir Fonoberov

Research paper thumbnail of Interfacial and Confined Optical Phonons in Wurtzite Nanocrystals

Research paper thumbnail of ELECTRONIC AND OPTICAL PROPERTIES OF SEMICONDUCTOR QUANTUM WIRES AND DOTS

Research paper thumbnail of Exciton radiative lifetime and the ``dead-layer'' effect in ZnO quantum dots

ZnO quantum dots (QDs) have recently attracted significant attention due to the proposed optoelec... more ZnO quantum dots (QDs) have recently attracted significant attention due to the proposed optoelectronic and nanoelectronic applications. We theoretically investigated the exciton radiative lifetime and the thickness of the ``dead-layer'' (layer where exciton does not penetrate) for ZnO QDs with radii from 1 to 3 nm [1]. Our calculations show that the dead layer formed near the QD surface is rather thick for ZnO QDs, what is attributed to the large hole-electron effective mass ratio in ZnO. The excited exciton states are also investigated as a function of the ZnO QD size. The small radiative lifetime and thick dead layer found in ZnO QDs can be beneficial for device applications owing to better luminescence and isolation of the exciton from surface defects [2]. The obtained results can be used for the optimization of ZnO QD arrays for optoelectronic applications. The authors acknowledge the support of MARCO and its Functional Engineered Nano Architectonics (FENA) Focus Center...

Research paper thumbnail of ZnO Quantum Dots: Physical Properties and Optoelectronic Applications

Journal of Nanoelectronics and Optoelectronics, 2006

Research paper thumbnail of Properties of GaN and ZnO quantum dots

... Quantum Dots Vladimir A. Fonoberov, Alexander A. Balandin Nano-Device Laboratory, Department ... more ... Quantum Dots Vladimir A. Fonoberov, Alexander A. Balandin Nano-Device Laboratory, Department of Electrical Engineering, University of California–Riverside, Riverside, CA, USA ... ˆ kx l ˆ kx + ˆk⊥ x h ˆk⊥ x 3 ˆ kx + 3 ˆ ky + ˆky − 3 ˆ kx 3 ˆ kx + 3 ˆ kz + ˆkz − 3 ˆ kx ...

Research paper thumbnail of Nonlinear Dynamics of Crime and Violence in Urban Settings

We perform analysis of data on crime and violence for 5,660 U.S. cities over the period of 2005-2... more We perform analysis of data on crime and violence for 5,660 U.S. cities over the period of 2005-2009 and uncover the following trends: 1) The proportion of law enforcement officers required to maintain a steady low level of criminal activity increases with the size of the population of the city; 2) The number of criminal/violent events per 1,000 inhabitants of

Research paper thumbnail of Electron and hole states in quantum dot quantum wells within a spherical eight-band model

Research paper thumbnail of Development of an eight-band theory for quantum dot heterostructures

Research paper thumbnail of Exciton states and optical transitions in colloidal CdS quantum dots: Shape and dielectric mismatch effects

Research paper thumbnail of Combustion of Methane in Microchannels

Volume 12: Micro and Nano Systems, Parts A and B, 2009

Combustion of Methane in Microchannels. [ASME Conference Proceedings 2009, 719 (2009)]. Sophie Lo... more Combustion of Methane in Microchannels. [ASME Conference Proceedings 2009, 719 (2009)]. Sophie Loire, Igor Mezić, Vladimir A. Fonoberov. Abstract. The interest in micropower generation using the high energy density provided ...

Research paper thumbnail of Modeling and Calibration of Energy Models for a DoD Building

Research paper thumbnail of Properties of polar optical phonons in wurtzite quantum dots

Wurtzite (WZ) ZnO and GaN quantum dots (QDs) have attracted significant attention as promising ca... more Wurtzite (WZ) ZnO and GaN quantum dots (QDs) have attracted significant attention as promising candidates for optoelectronic applications. To enable the interpretation of the optical response of such QDs, we derive an integral equation that defines both interface and confined polar optical phonon modes in WZ QDs of arbitrary shapes [1]. The analytical solution of the derived equation is found for spheroidal QDs [2]. While the frequency of the confined polar optical phonons in zincblende QDs is equal to that of the bulk crystal, the confined optical phonons in WZ QDs are shown to have a discrete spectrum of frequencies different from those of the bulk crystal. The obtained results have been proven useful for the accurate prediction of interface and confined optical phonon frequencies in the novel class of QDs. This research has been supported in part by the ONR Young Investigator Award to A.A.B. [1] V.A. Fonoberov and A.A. Balandin, Phys. Rev. B 70, in press (Dec. 15, 2004). [2] V.A....

Research paper thumbnail of Calibration of a Building Energy Model Considering Parametric Uncertainty

Research paper thumbnail of Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

Physical Review B, 2004

We theoretically investigate exciton states of colloidal nearly spherical ZnO nanocrystals with d... more We theoretically investigate exciton states of colloidal nearly spherical ZnO nanocrystals with diameters from 2nmto6nm . The sizes of considered ZnO nanocrystals are chosen to be slightly larger than the exciton Bohr radius of bulk ZnO. A number of characteristic features of excitons are revealed in this intermediate quantum confinement regime. The exciton center of mass is found to be prolate along the c axis of wurtzite ZnO and squeezed to the center of the ZnO nanocrystal, thus forming a dead layer near the nanocrystal surface. The thickness of the exciton dead layer is found to increase with the nanocrystal size reaching the value of about 1.6nm for the nanocrystal with diameter of 6nm . Based on our calculations we proposed an analytical approximation for the exciton radiative-lifetime dependence on radius R in ZnO nanocrystal written as tau0/[1+(R/R0)3] with tau0=73.4ps and R0=2.55nm . Presented results and proposed analytical approximation can be used for interpretation of experimental data, and optimization of ZnO quantum dot structures for optoelectronic applications.

Research paper thumbnail of Global sensitivity/uncertainty analysis for agent-based models

Reliability Engineering & System Safety, 2013

Research paper thumbnail of Interface and confined optical phonons in wurtzite nanocrystals

Research paper thumbnail of Uncertainty as a stabilizer of the head-tail ordered phase in carbon-monoxide monolayers on graphite

Research paper thumbnail of Interface and confined polar optical phonons in spherical ZnO quantum dots with wurtzite crystal structure

physica status solidi (c), 2004

Research paper thumbnail of Low-frequency vibrational modes of viruses used for nanoelectronic self-assemblies

physica status solidi (b), 2004

Research paper thumbnail of Electron states in rectangular quantum well wires (single wires, finite and infinite lattices)

Journal of Physics: Condensed Matter, 2000

Research paper thumbnail of Interfacial and Confined Optical Phonons in Wurtzite Nanocrystals

Research paper thumbnail of ELECTRONIC AND OPTICAL PROPERTIES OF SEMICONDUCTOR QUANTUM WIRES AND DOTS

Research paper thumbnail of Exciton radiative lifetime and the ``dead-layer'' effect in ZnO quantum dots

ZnO quantum dots (QDs) have recently attracted significant attention due to the proposed optoelec... more ZnO quantum dots (QDs) have recently attracted significant attention due to the proposed optoelectronic and nanoelectronic applications. We theoretically investigated the exciton radiative lifetime and the thickness of the ``dead-layer'' (layer where exciton does not penetrate) for ZnO QDs with radii from 1 to 3 nm [1]. Our calculations show that the dead layer formed near the QD surface is rather thick for ZnO QDs, what is attributed to the large hole-electron effective mass ratio in ZnO. The excited exciton states are also investigated as a function of the ZnO QD size. The small radiative lifetime and thick dead layer found in ZnO QDs can be beneficial for device applications owing to better luminescence and isolation of the exciton from surface defects [2]. The obtained results can be used for the optimization of ZnO QD arrays for optoelectronic applications. The authors acknowledge the support of MARCO and its Functional Engineered Nano Architectonics (FENA) Focus Center...

Research paper thumbnail of ZnO Quantum Dots: Physical Properties and Optoelectronic Applications

Journal of Nanoelectronics and Optoelectronics, 2006

Research paper thumbnail of Properties of GaN and ZnO quantum dots

... Quantum Dots Vladimir A. Fonoberov, Alexander A. Balandin Nano-Device Laboratory, Department ... more ... Quantum Dots Vladimir A. Fonoberov, Alexander A. Balandin Nano-Device Laboratory, Department of Electrical Engineering, University of California–Riverside, Riverside, CA, USA ... ˆ kx l ˆ kx + ˆk⊥ x h ˆk⊥ x 3 ˆ kx + 3 ˆ ky + ˆky − 3 ˆ kx 3 ˆ kx + 3 ˆ kz + ˆkz − 3 ˆ kx ...

Research paper thumbnail of Nonlinear Dynamics of Crime and Violence in Urban Settings

We perform analysis of data on crime and violence for 5,660 U.S. cities over the period of 2005-2... more We perform analysis of data on crime and violence for 5,660 U.S. cities over the period of 2005-2009 and uncover the following trends: 1) The proportion of law enforcement officers required to maintain a steady low level of criminal activity increases with the size of the population of the city; 2) The number of criminal/violent events per 1,000 inhabitants of

Research paper thumbnail of Electron and hole states in quantum dot quantum wells within a spherical eight-band model

Research paper thumbnail of Development of an eight-band theory for quantum dot heterostructures

Research paper thumbnail of Exciton states and optical transitions in colloidal CdS quantum dots: Shape and dielectric mismatch effects

Research paper thumbnail of Combustion of Methane in Microchannels

Volume 12: Micro and Nano Systems, Parts A and B, 2009

Combustion of Methane in Microchannels. [ASME Conference Proceedings 2009, 719 (2009)]. Sophie Lo... more Combustion of Methane in Microchannels. [ASME Conference Proceedings 2009, 719 (2009)]. Sophie Loire, Igor Mezić, Vladimir A. Fonoberov. Abstract. The interest in micropower generation using the high energy density provided ...

Research paper thumbnail of Modeling and Calibration of Energy Models for a DoD Building

Research paper thumbnail of Properties of polar optical phonons in wurtzite quantum dots

Wurtzite (WZ) ZnO and GaN quantum dots (QDs) have attracted significant attention as promising ca... more Wurtzite (WZ) ZnO and GaN quantum dots (QDs) have attracted significant attention as promising candidates for optoelectronic applications. To enable the interpretation of the optical response of such QDs, we derive an integral equation that defines both interface and confined polar optical phonon modes in WZ QDs of arbitrary shapes [1]. The analytical solution of the derived equation is found for spheroidal QDs [2]. While the frequency of the confined polar optical phonons in zincblende QDs is equal to that of the bulk crystal, the confined optical phonons in WZ QDs are shown to have a discrete spectrum of frequencies different from those of the bulk crystal. The obtained results have been proven useful for the accurate prediction of interface and confined optical phonon frequencies in the novel class of QDs. This research has been supported in part by the ONR Young Investigator Award to A.A.B. [1] V.A. Fonoberov and A.A. Balandin, Phys. Rev. B 70, in press (Dec. 15, 2004). [2] V.A....

Research paper thumbnail of Calibration of a Building Energy Model Considering Parametric Uncertainty

Research paper thumbnail of Radiative lifetime of excitons in ZnO nanocrystals: The dead-layer effect

Physical Review B, 2004

We theoretically investigate exciton states of colloidal nearly spherical ZnO nanocrystals with d... more We theoretically investigate exciton states of colloidal nearly spherical ZnO nanocrystals with diameters from 2nmto6nm . The sizes of considered ZnO nanocrystals are chosen to be slightly larger than the exciton Bohr radius of bulk ZnO. A number of characteristic features of excitons are revealed in this intermediate quantum confinement regime. The exciton center of mass is found to be prolate along the c axis of wurtzite ZnO and squeezed to the center of the ZnO nanocrystal, thus forming a dead layer near the nanocrystal surface. The thickness of the exciton dead layer is found to increase with the nanocrystal size reaching the value of about 1.6nm for the nanocrystal with diameter of 6nm . Based on our calculations we proposed an analytical approximation for the exciton radiative-lifetime dependence on radius R in ZnO nanocrystal written as tau0/[1+(R/R0)3] with tau0=73.4ps and R0=2.55nm . Presented results and proposed analytical approximation can be used for interpretation of experimental data, and optimization of ZnO quantum dot structures for optoelectronic applications.

Research paper thumbnail of Global sensitivity/uncertainty analysis for agent-based models

Reliability Engineering & System Safety, 2013

Research paper thumbnail of Interface and confined optical phonons in wurtzite nanocrystals

Research paper thumbnail of Uncertainty as a stabilizer of the head-tail ordered phase in carbon-monoxide monolayers on graphite

Research paper thumbnail of Interface and confined polar optical phonons in spherical ZnO quantum dots with wurtzite crystal structure

physica status solidi (c), 2004

Research paper thumbnail of Low-frequency vibrational modes of viruses used for nanoelectronic self-assemblies

physica status solidi (b), 2004

Research paper thumbnail of Electron states in rectangular quantum well wires (single wires, finite and infinite lattices)

Journal of Physics: Condensed Matter, 2000