Optical properties of InGaAs/InAIAs diffused double quantum wells

Choy, Wallace C. H.

doi:10.1063/1.372284

Cited by 8 publications

(9 citation statements)

References 27 publications

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“…Once the quantum confinement structures and the material compositions are determined, the emission peak can be confirmed. For dynamic methods, external electric field (see, for example, [18,19]), acoustic wave [20], and temperature [21,22] can be used to tune the transition energy. By reducing the temperature from 283 K to 4:2 K, the dominated peak of the conventional ZnSe photoluminescence (PL) blueshifts for about 100 meV from ∼2:7 to ∼2:8 eV [21,22].…”

Section: Introductionmentioning

confidence: 99%

Largely extended light-emission shift of ZnSe nanostructures with temperature

Choy¹,

Leung²

2011

Appl. Opt.

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ZnSe nanowires and nanobelts with zinc blende structure have been synthesized. The morphology and the growth mechanisms of the ZnSe nanostructures will be discussed. From the photoluminescence (PL) of the ZnSe nanostructures, it is interesting to note that red color emission with only a single peak at the photon energy of 2 eV at room temperature is obtained while the typical bandgap transition energy of ZnSe is 2:7 eV. When the temperature is reduced to 150 K, the peak wavelength shifts to 2:3 eV with yellowish emission and then blue emission with the peak at 2:7 eV at temperature less than 50 K. The overall wavelength shift of 700 meV is obtained as compared to the conventional ZnSe of about 100 meV (i.e., sevenfold extension). The ZnSe nanostructures with enhanced wavelength shift can potentially function as visible light temperature-indicator. The color change from red to yellowish and then to blue is large enough for the nanostructures to be used for temperature-sensing applications. The details of PL spectra of ZnSe at various temperatures are studied from (i) the spectral profile, (ii) the half-width half-maximum, and (iii) the peak photon energy of each of the emission centers. The results show that the simplified configuration coordinate model can be used to describe the emission spectra, and the frequency of the local vibrational mode of the emission centers is determined.

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Section: Introductionmentioning

confidence: 99%

Largely extended light-emission shift of ZnSe nanostructures with temperature

Choy¹,

Leung²

2011

Appl. Opt.

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“…With the subband structure, the optical properties of DFQW can be modeled [11], [22]. Using the density matrix theory, the material gain and the change in refractive index can be obtained as (6) (7) where is the optical matrix element and , are the Fermi distribution functions for electrons and holes, respectively.…”

Section: Modeling Of Diffused Qwsmentioning

confidence: 99%

“…are the elastic constants. Following the method, (4) and (5) have been substituted to the 4 4 Lutinger-Kohn Hamiltonian [11] for determining the subband structures of HH and LH so that the coupling between HH and LH, i.e., bandmixing effect, can be taken into account. Meanwhile, (3) is applied to one-particle Schrödinger-like equation for calculating the conduction band.…”

Section: Modeling Of Diffused Qwsmentioning

confidence: 99%

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Theoretical analysis of diffused quantum-well lasers and optical amplifiers

Choy

Chan

2003

IEEE J. Select. Topics Quantum Electron.

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Abstract-Diffused quantum-well (QW) distributed feedback (DFB) lasers and optical amplifiers will be theoretically analyzed in this paper. For DFB lasers, a design rule will be proposed and the validity of the design rule will be discussed with respect to changes in the injected carrier density. The range of grating period, which can be used in the design, is discussed. As a consequence, the maximum tuning range of the emission wavelength can be estimated without involving the time-consuming self-consistent simulation. The features of polarization independence of optical amplifiers achieved by using diffused QWs are also discussed. Our theoretical results successfully explain why polarization independence can achieve in the long-wavelength tail of the modal gain and absorption coefficient but not at photon energies above the transition edge. This explanation applies to other tensile-strained QWs for polarization-independent applications. The understanding is crucial for optimizing polarization-independent devices. To conclude, our analysis of the diffused QW optical devices demonstrates that QW intermixing technology is a practical candidate for not only realizing monolithic photonic integrated circuit, but also enhancing optical device performance.Index Terms-Diffused quantum well (DFQW), distributed feedback (DFB) lasers, optical amplifiers, polarization independence, quantum-well interdiffusion, quantum-well intermixing, wavelength tuning.

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“…The dielectric functions are used to determine [15], [17], which is given by (7) where and are the real and imaginary parts of the dielectric function respectively, and are given by (8) (9) where and denotes the contribution from -valley, and denotes the contribution from -valley, and denotes the contribution from -valley, denotes the contribution from other transitions to , and denotes the contribution from the indirect transitions to . The quantum confinement affects primarily the contribution of the transitions in the -valley, and thus and , while the contributions of the bulk-like -and -valleys and all other transitions above the DQW, which contribute to the real and imaginary dielectric functions, are obtained using a bulk calculation [18].…”

Section: B Optical Propertiesmentioning

confidence: 99%

Asymmetric double-quantum-well phase modulator using surface acoustic waves

Choy

Weiss

1998

IEEE J. Quantum Electron.

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Abstract-An AlGaAs-GaAs asymmetric double-quantum-well (DQW) optical phase modulator using surface acoustic waves is investigated theoretically. The optimization steps of the DQW structure, which so far have not been reported in detail, are discussed here. The optimized phase modulator structure is found to contain a five-period QDW active region. A surface acoustic wave induces a potential field which provides the phase modulation. Analysis of the modulation characteristics show that by using the asymmetric DQW, the large change of the induced potential at the surface and thus large modification of the quantum-well (QW) structure can be utilized. The modification of each QW structure is consistent, although this consistency is not always preserved in typical surface acoustic wave devices. Consequently, the change of refractive index in each of the five DQW's is almost identical. Besides, the change of effective refractive index is ten times larger here in comparison to a modulator with a five-period single QW as the active region and thus produces a larger phase modulation. In addition, a long wavelength and a low surface acoustic wave power required here simplify the fabrication of surface acoustic wave transducer and the acoustooptic phase modulator.Index Terms-Acoustooptic device, double quantum well, electrooptical modulation, piezoelectric effect of surface acoustic waves, surface acoustic wave modulator.

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Optical properties of InGaAs/InAIAs diffused double quantum wells

Cited by 8 publications

References 27 publications

Largely extended light-emission shift of ZnSe nanostructures with temperature

Largely extended light-emission shift of ZnSe nanostructures with temperature

Theoretical analysis of diffused quantum-well lasers and optical amplifiers

Asymmetric double-quantum-well phase modulator using surface acoustic waves

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