Quantitative model for the kinetics of compositional intermixing in GaAs-AlGaAs quantum-confined heterostructures

Helmy, Amr S.; Aitchison, J. S.; Marsh, J.H.

doi:10.1109/2944.720476

Cited by 8 publications

(7 citation statements)

References 28 publications

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“…Peyre et al [175] who measured the transition energies of three inter band states (E1-HH1, E1-LH1, E2-HH2) as a function of QWI using the technique of low temperature excitonic reflectivity and 2. Helmy et al [82] who used photoluminescence excitation spectroscopy (PLE) to measure eight (E1-HH1, E1-LH1, E1-HH2, E1-HH3, E2-HH1, E1-LH2, E2-LH1, E2-HH2) inter-band transitions.…”

Section: Discussionmentioning

confidence: 99%

“…Fick's first law (Equation 5.1) states that the rate of transfer F of a diffusing substance through a unit surface area of a plane is proportional to the concentra tion (C) gradient in the direction normal to that plane (z). The proportionality constant is the diffusion coefficient, D. Fick's second law (Equation 5.2) is only valid for the case where D is independent of C. Helmy et al [82] suggest this is not a good assumption for a semiconductor, since the diffusion coefficient is a function of position (^)and concentration (C):…”

Section: Theorymentioning

confidence: 99%

“…Peyre et al [175] showed that Fickian diffusion (D independent of concentration) was a valid assumption, whereas Helmy et al [82] suggested that a symmetric exponential profile was superior. As discussed in §2.3 we assume that QWI is described by Fickian diffusion.…”

Section: Theoretical Modelmentioning

confidence: 99%

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III-V Detectors

2010

Infrared Detectors

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The quantum-well infrared photodetector (QWIP) is a relatively new type of semiconductor detector which has a clearly defined spectral response. This study shows that the infrared spectral response of a QWIP can be fine tuned. We have fabricated AlGaAs-GaAs QWIPs, and used proton implantation and rapid thermal annealing to tune the infrared spectral response of these QWIPs by up to 1.4 pm. Multiple proton implants at energies between 200 and 400 keV were used to create homogeneous quantum-well intermixing throughout the de vices' multiple-quantum-well structure. Photoluminescence and photoresponse measurements were used to study the effect of proton implantation on QWIPs for a series of doses up to 3.5 x 1015 protons cm-2. By using a mask during im plantation, a method of constructing a colour sensitive array is proposed. The dynamics in quantum-wells with similar properties to QWIPs were investigated. The capture of electron-hole pairs into a quantum-well increased after the sam ple was intermixed. Thus intermixed QWIPs may exhibit improved electrical response bandwidths. The dynamic properties of a sawtooth superlattice (<5-doped nipt) were ex amined by photoluminescence spectroscopic techniques. The dynamic properties of the sawtooth superlattice were probed using time resolved photoluminescence and carrier lifetime measurements. £-doped sawtooth superlattices are shown to have a tunable bandgap as well as an intensity tunable carrier lifetime. These properties may prove useful in the development of a wavelength tunable inter subband nipi infrared detector. Thermal quenching of photoluminescence from GaAs-InGaAs and AlGaAs-GaAs quantum-wells has been shown to be dependent on the intensity of excita tion. We believe this intensity dependence is related to the presence of saturable non-radiative recombination paths via hetero-interface defects. Additionally, an increase in photoluminescence intensity as a function of temperature has been observed at low temperatures. These results are linked to the presence of sat urable defect states, possibly surface states. Firstly I would like to thank my supervisor, Professor Mike Gal for everything he has taught me during my studies. His enthusiasm, knowledge and advice have helped maintain the direction of this thesis, while the responsibility and freedom he has given me has allowed me to follow some of my own odd ideas. Dr C. Jagadish has been a constant source of encouragement and useful collaboration, both with his group at the Australian National University and with the Chinese Academy of Sciences. Without the expertise, time and facilities of his group this project would not have been possible. Dr. Lap van Dao has constructed the photoluminescence up-conversion sys tem in our laboratory. His skill in lasers and optics is exceptional. Thanks to Lap for many discussions on carrier dynamics in quantum-wells. Sincere thanks to Dr. Nancy Lumpkin for spending so many hours teaching me semiconductor device fabrication and for sharing her excellent methods with me. The fabri...

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Section: Discussionmentioning

confidence: 99%

Section: Theorymentioning

confidence: 99%

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III-V Detectors

2010

Infrared Detectors

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“…This is due to the introduction of group-III vacancies at the sample/ dielectric interface which have a tendency to interdiffuse species residing on the group-III sublattice only. 7 In the case of the InGaAs/ GaAs MQW the intermixing takes place on the group-III sublattice, while in the InGaAs/ InGaAsP MQWs, because the same group-III composition is used in the wells and barriers the compositional gradient is only on the group-V sublattice and therefore remains intact in the presence of group-III vacancies. Therefore, we conclude that the group-V sublattice is more stable and less likely to interdiffuse at elevated temperatures than the group-III sublattice in samples encapsulated by SiO x N y .…”

mentioning

confidence: 99%

Multiple-band-edge quantum-well intermixing in the InGaAs∕InGaAsP∕InGaP material system

Skogen¹,

Coldren

Raring

et al. 2005

Applied Physics Letters

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“…However, this assumption would indicate that H 2 O and air in the film pores play a key role in assisting and preventing Ga outdiffusion and hence QWI, respectively. 18 We have demonstrated control of the extent of QWI in various GaAs/AlGaAs heterostructures by exposing the SiO 2 films used in the process of impurity free vacancy disordering to an oxygen plasma, produced by a reactive ion etching machine. Control was observed for doped and undoped GaAs/AlGaAs samples.…”

mentioning

confidence: 99%

Control of silica cap properties by oxygen plasma treatment for single-cap selective impurity free vacancy disordering

Helmy

Murad

Bryce

et al. 1999

Applied Physics Letters

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By exposing the SiO2 films used as annealing caps in the process of impurity free vacancy disordering (IFVD) to an oxygen plasma, which is produced in a reactive ion etching machine, the effect of the exposed caps on quantum well intermixing can be substantially controlled. The effect of the oxygen treatment is manifested in inhibiting the Ga outdiffusion from GaAs/AlGaAs heterostructures. A selective IFVD process using identical silica caps has been obtained by selective exposure of the caps to oxygen plasma. Differential band gap shifts in excess of 100 meV were achieved with control samples exhibiting band gap shifts less than 10 meV.

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Quantitative model for the kinetics of compositional intermixing in GaAs-AlGaAs quantum-confined heterostructures

Cited by 8 publications

References 28 publications

III-V Detectors

III-V Detectors

Multiple-band-edge quantum-well intermixing in the InGaAs∕InGaAsP∕InGaP material system

Control of silica cap properties by oxygen plasma treatment for single-cap selective impurity free vacancy disordering

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