Three-cation intermixed InGaAs/InAlAs quantum well structures and their optical gain properties

Multiple cations intermixed In053Ga047As/In052A104,As quantum well structure with 60 A well width is investigated by using the expanded form of Fick's second law. It was found that a maximum compressive strain of 0.64% is obtained when annealing time reaches 3 hours at 812 °C in the indium sublattice. For a small interdiffusion, i.e. 1 to 1.5 hrs, the subband separation between the lowest heavy and light hole states is at its greatest. This is a major contribution to the band structure and averaged density of states, thus enhancement in optical gain up to 40% is obtained. For a large interdiffusion, i.e. up to 6 hrs., a large blue shift of the peak gain from 0.842 to 1.016eV is observed.published_or_final_versio

Theory of critical layer thickness of noncontant quantum-well width produced by interdiffusion and its optoelectronics consequence

In this paper, the concept of critical layer thickness is applied to the interdiffused quantum well (DFQW) structure. For the as-grown InGaAs/InP lattice matched quantum well, the interdiffusion process will induce in-plane strain into the DFQW forming a lattice mismatched system. The relation between the as-grown well width (Lz) and the diffusion length (Ld) for formation of dislocation is presented.published_or_final_versio

Analysis of three types of interdiffusion process in InGaAs/InP quantum-well and their devices implications

The optical properties of Ino 53Gao 47AS/I11P single quantum well (QW) (with an as-grown well width of 60Å structures) interdiffused with different cation and anion interdiffusion rates have been theoretically analyzed for applications in optoelectronics. The interdiffusion of InGaAs/InP QW structures is complicated as interdiffusion can occur for either (i) only group-Ill (In,Ga), (ii) group-V (As,P), or (iii) both group-Ill and group-V sublattices. Depending on the resulting composition profiles, the shifts (blue or red) of the transition energies can be tuned to wavelengths between 1.3µm to 1.55µm for device applications. The results show that the control of the rates of cation and anion interdiffusion offers interesting possibilities for designing optoelectronic devices such as modulators and lasers.published_or_final_versio

Bandstructure of Interdiffused InGaN/GaN Quantum Well

Quantum well composition intermixing is a thermal induced interdiffusion of the constituent atoms through the hetero- interface. The intermixed structures created by both impurity induced and impurity-free vacancy promoted processes have recently attracted high attention. In recent years, blue green LED and laser of III-nitride semiconductors have attracted a large amount of interest. This is mainly due to its large bandgap range from 1.89eV to 3.44eV. InGaN/GaN single quantum well structures have been used to achieve high lumens blue and green light emitting diodes. In this paper, we will present the band structure of strained InGaN/GaN single quantum well under the influence of interdiffusion. Band structure is a fundamental aspect in determining the electronic and optical properties of the materials such as optical gain, refractive index, absorption, etc.published_or_final_versio

Interdiffusion-induced polarization-independent optical gain of an InGaAs-InP quantum-well with carrier effects

A theoretical study of the polarization-independent optical gain using group V sublattice interdiffusion in InGaAs-InP quantum wells (QW's) is presented here. The reverse bias and carrier effects on the subband structures, transition energy, and optical gain of the interdiffused QW are discussed. The interdiffused QW structures are optimized in terms of their subband structure, carrier density, structural parameters, and properties of optical gain spectra. The results show that an optimized interdiffused QW structure can produce polarization-independent optical gain over a range of operation wavelengths around 1.5 μm, although the differential gain and linewidth enhancement factor are slightly degraded. The required tensile strain for the polarization-independent optical properties of a lattice-matched QW structure may be generated using interdiffusion. These results suggest that polarization-independent optical devices can be fabricated using interdiffusion in a lattice-matched InGaAsP QW structure.published_or_final_versio

Effect of interdiffusion on the subbands in an In0.65Gs0.35As/GaAs multiple-quantum well structure on GaAs substrate at 1.55µm operation wavelength

Analysis, of high indium concentration in interdiffused Ino.65Gso.35As/GaAs multiple quantum well (MQW) structure on GaAs Substrate is being studied. This material can achieve operating wavelengths around 1.5µm for applications in fiber optics communications. The large lattice mismatch problem (over 4.5% in this study) can be solved by using a linearly-graded InGaAs buffer layer for reducing any dislocation between the adjacent layers. Interdiffusion in the MQW structure can modify the composition profile in order to tailor the optical absorption and refraction properties. Results show that this system can have promising device performance operates at around 1.55nm and which base on the more matured and reliable GaAs technology.published_or_final_versio

Temperature-dependent photoluminescence of GaInP/AlGaInP multiple quantum well laser structure grown by metalorganic chemical vapor deposition with tertiarybutylarsine and tertiarybutylphosphine

A GaInP/AlGaInP multiple quantum well laser structure was grown by low-pressure metalorganic chemical vapor deposition with tertiarybutylarsine and tertiarybutylphosphine. Laser diodes fabricated from this structure lased at room temperature. Photoluminescence ~PL! measurements were performed from 10 to 230 K. The PL energy increased with temperature from 10 to 70 K and decreased above 70 K. The former was attributed to thermal activation of trapped carriers due to localization in the quantum wells, while the latter was attributed to temperature-induced band-gap shrinkage. The PL intensity as a function of temperature was fitted by employing two nonradiative recombination mechanisms with good agreement, resulting in two activation energies that correspond to losses of photogenerated carriers to nonradiative centers. © 2003 American Institute of Physics.published_or_final_versio