Simulation of infrared pump-probe spectroscopy in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>n</mml:mi></mml:math>-type quantum wells

Sanders, G. D.; Stanton, C. J.

doi:10.1103/physrevb.57.9148

Cited by 10 publications

(12 citation statements)

References 23 publications

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“…10,39 Thus the time dependent conduction and valence electron distribution functions, f n c ͑k͒ and f n Ј v ͑k͒, are functions of the magnitude of k.…”

Section: Carrier Dynamicsmentioning

confidence: 99%

Carrier dynamics and coherent acoustic phonons in nitride heterostructures

Sanders

Stanton

2006

Phys. Rev. B

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We model generation and propagation of coherent acoustic phonons in piezoelectric InGaN / GaN multiquantum wells embedded in a p-i-n diode structure and compute the time resolved reflectivity signal in simulated pump-probe experiments. Carriers are created in the InGaN wells by ultrafast pumping below the GaN band gap and the dynamics of the photoexcited carriers is treated in a Boltzmann equation framework. Coherent acoustic phonons are generated in the quantum well via both deformation potential electron-phonon and piezoelectric electron-phonon interaction with photogenerated carriers, with the latter mechanism being the dominant one. Coherent longitudinal acoustic phonons propagate into the structure at the sound speed modifying the optical properties and giving rise to a giant oscillatory differential reflectivity signal. We demonstrate that coherent optical control of the differential reflectivity can be achieved using a delayed control pulse.

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“…10,39 Thus the time dependent conduction and valence electron distribution functions, f n c ͑k͒ and f n Ј v ͑k͒, are functions of the magnitude of k.…”

Section: Carrier Dynamicsmentioning

confidence: 99%

Carrier dynamics and coherent acoustic phonons in nitride heterostructures

Sanders

Stanton

2006

Phys. Rev. B

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“…Key: n-mod = modulation doped with donor impurities, 1QW = calculations were performed on a single quantum-well, T = the lattice temperature of the sample, FEL = free electron laser, At = pulse-width of hypothetical laser pulse and I0 = intensity of hypothetical laser. 0.5mJ/cm2 [195] 4.55 GaAs/AlxGai-* As 100A n-mod 8 x 1010cm-2…”

Section: B4 a Comparison Of Mbe And Movpementioning

confidence: 99%

“…Key: n-mod = mod ulation doped with donor impurities, n-doped = sample was uniformly doped with donor impurities, T = the lattice temperature of the sample, FEL = free electron laser, PV = Photovoltage measurement, PL = Photoluminecence mea surement, CW = Continous Wave, VIS implies interband excitation, whilst IR implies intersubband excitation, MC = Monte-Carlo calculation performed using experimental data, At = pulse-width of laser pulse and /0 = intensity of laser. Time resolved pump-probe spectroscopy: Pump-probe absorption (trans mission) spectroscopy of semiconductor quantum-wells has been conducted using parametric IR-generation [125,3,148,149,7,103,206], far-IR-free electron lasers [162,86,163,195] and inter-band optical excitation [94]. In these experiments the "pump" pulse creates a population of excited carriers, whilst a much weaker "probe" pulse measures the absorption (transmission).…”

Section: C2 Review Of Experimental Studiesmentioning

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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Ultrafast Nonequilibrium Dynamics of Intersubband Excitations in Quasi-two-dimensional Semiconductors

Woerner¹,

Elsaesser²

2001

Ultrafast Phenomena in Semiconductors

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Simulation of infrared pump-probe spectroscopy inn-type quantum wells

Cited by 10 publications

References 23 publications

Carrier dynamics and coherent acoustic phonons in nitride heterostructures

Carrier dynamics and coherent acoustic phonons in nitride heterostructures

III-V Detectors

Ultrafast Nonequilibrium Dynamics of Intersubband Excitations in Quasi-two-dimensional Semiconductors

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