E.Y. Lin

Accurate model including Coulomb-enhanced and Urbach-broadened absorption spectrum of direct-gap semiconductors

An accurate absorption model including Coulomb interaction and Urbach-broadened band edge has been demonstrated for direct bandgap semiconductors. We propose a steep-edged compound Lorentzian line-shape function for modeling the Urbach tail and the line broadening of exciton absorptions. The results of applying this fitting procedure to room-temperature and low-temperature absorption spectra of GaAs, InP, and InAs are presented, and a consistent set of band parameters are extracted. The analytical absorption model is suitable for a complete closed-form Kramers-Kronig transform of the absorption spectrum to obtain the refractive-index spectrum.

Modulation-Doped InGaAlAs/InP Semiconductor Optical Amplifier Structures Grown by Molecular Beam Epitaxy

Semiconductor optical amplifier (SOA) structures have been designed and grown by molecular beam epitaxy for multi-functional integration of 1.55-µm photonic devices on InP. Triple n-type modulation-doped, strain-balanced compact quantum wells (QWs) are designed to provide desirable gain characteristics under forward bias and clean index changes under reverse bias. The largest refractive index changes with low levels of electroabsorption have been obtained for a sample with modulation doping of 4.27 ×1011 cm-2 per QW and with a hole-stopping barrier.

340nm blue-shift in InGaAs/InAlAs quantum dots processed by SiO 2 sputtering and rapid thermal annealing

The atomic intermixing effects on emission wavelength blue-shift for self-assembled InGaAs/InAlAs quantum dots on InP substrate were investigated. A large blue-shift upto 343 nm, from lambda=1632 nm to 1289 nm, was obtained by SiO2 sputtering deposition and rapid thermal annealing at 800degC.

Improved modeling of Coulomb-enhanced and Urbach-broadened absorption edge of direct-gap semiconductors for band-parameter extraction

An improved model for the Coulomb-enhanced and Urbach-broadened absorption spectrum that can be used to extract the band parameters for the band-edge region as well as to calculate the refractive index spectrum accurately.

Quantum Well Intermixing in InGaAs/InGaAlAs Structures by Using ICP-RIE and SiO2 Sputtering

A quantum well intermixing process combining ICP-RIE and SiO2 sputtering was investigated for the InGaAs/InGaAlAs multi-quantum wells. Optimal conditions including ICP-RIE etching depth, SiO2 deposition, and RTA process were obtained for a 60-nm blueshift.

A band-to-band Coulomb interaction model for refractive indices of Al/sub x/Ga/sub 1-x/As and InGaAs ternary materials at photon energies near and above the band-gap

Refractive indices of ternary materials at photon energies somewhat above the bandgap have been modeled from Kramers-Kronig transform through an absorption model with Coulomb interaction and a double-Lorentzian broadening in employing Vegards law

Broad and flat emission spectrum from InGaAs/InGaAlAs asymmetric multiple quantum wells: effect of well-width and modulation-doping profiles

Asymmetric InGaAs/InGaAlAs multi-quantum wells exhibit a = 1.55 mum broad and flat emission spectrum with 3-dB bandwidth up to 2500 Aring. Emission spectra and laser diodes by the effects of well-width and modulation-doping profiles are presented

Empirical formulas including Coulomb interaction for refractive indices of GaAs and InP-based materials at photon energies near and above the bandgap

Formulas for extrapolation of refractive indices of III-V materials to energies somewhat above the band gap have been developed from a model that takes into account of both Coulomb interaction and Lorentz broadening.

Modulation-doped Asymmetric Multi-Quantum-Well Structures for Flat Broadband Gain Spectrum

Asymmetric InGaAs/InGaAlAs multiple quantum well structures containing three pairs of different well widths have been grown by MBE. P-type modulation-doping has been found to significantly improve the flatness of the remarkably broad photoluminescence spectrum.

Photocurrent and differential absorption spectra of InGaAsN single- and double-quantum-well structures grown by molecular beam epitaxy

We report the photocurrent and differential absorption spectra of an InGaAsN single- and a double-quantum-well (SQW and DQW) structure measured at different reverse bias. The DQW structure shows an additional enhancement in electroabsorption of a maximum /spl Delta//spl alpha/ /spl sim/ 14400 cm/sup -1/, which is 2.6 times larger than the maximum /spl Delta//spl alpha/ /spl sim/ 5400 cm/sup -1/ of the SQW sample.