Influence of ionized impurities on the linewidth of intersubband transitions in GaAs/GaAlAs quantum wells

Dupont, Emmanuel; Delacourt, D.; Papillon, D.; Schnell, J. P.; Papuchon, M.

doi:10.1063/1.107082

Cited by 41 publications

(25 citation statements)

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“…In view of our results and using a self-consistent solution, we reanalyzed a previous experiment where the broadening was measured as a function of donor separation from the well. 12 We deduce that the main cause for the reduction in linewidth observed in donor-well separation was the resultant reduction in the well's ground state population rather than the increased donor-electron separation itself.…”

Section: Report Documentation Pagementioning

confidence: 92%

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Direct measurement of population-induced broadening of quantum well intersubband transitions

Almogy

O’Brien

et al. 1997

Applied Physics Letters

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The dependence of the absorption spectral linewidth of quantum well intersubband transitions on the electron population in the well is experimentally demonstrated. We show that the dependence of the spectral linewidth on the population is substantial and accounts for some of the broadening previously attributed to donor scattering. © 1997 American Institute of Physics. ͓S0003-6951͑97͒04530-0͔In the single band model, also known as the parabolic effective mass model, intersubband transitions in quantum wells ͑QWs͒ are discrete. In practice, electron-electron interaction, QW width nonuniformity, electron interactions with rough interfaces and with impurities and their enhancement by electric fields, and the optical and acoustic phonons contribute to the experimentally observed linewidth of intersubband transition in QWs. [1][2][3][4][5] There have been quite a few theoretical reports to explain the experimental observation, [1][2][3][4][5][6][7][8] and, there has been controversy over the contribution of population density to the intersubband broadening. Bandara et al. 6,7 predicted that the dependence of the exchange interaction on the in-plane momentum (k ʈ ) could contribute a substantial fraction of experimentally observed linewidths. Zaluzny, 8 on the other hand, claimed that the k ʈ dependence is offset by the depolarization and excitonlike manybody effects. In this letter, we report on the experimental study of the dependence of intersubband transition broadening on electron population using a structure consisting of 50 periods of an asymmetric coupled double QWs ͑ACDQWs͒. External applied bias was used to shift the population between the coupled QWs whose absorption was measured with a monolithically integrated QW infrared photodetector ͑QWIP͒ directly on the ACDQW structure. 9,10 The monolithically integrated structure was grown by molecular beam epitaxy on a ͑100͒ semi-insulating GaAs substrate. The ACDQWs consisted of an undoped 9-nmthick GaAs narrow well, an undoped 3-nm-thick Al 0.4 Ga 0.6 As barrier, and a selectively doped 10.8-nm-thick GaAs wide well. The wide well was nominally Si doped to 2ϫ10 18 cm Ϫ3 from 0.5 to 4.5 nm away from the barrier. The periods were separated by 42.2 nm of undoped Al 0.4 Ga 0.6 As layers. This structure was designed to provide the largest possible charge transfer between the narrow well and the wide well with external applied bias. The absorption spectrum of the monolithically integrated QWIP was designed to overlap with that of the narrow well in the ACDQWs, while the wide well in the ACDQWs had an absorption spectrum peaked at the tail of the QWIP photoresponse spectrum. The QWIP was separated from the ACDQW structure by a 0.6-m-n ϩ -GaAs and a 0.2-m GaAs buffer layer. The QWIP consisted of 15 periods of 6.5-nm-thick Si-doped GaAs wells with nominal doping density of 1.1ϫ10 12 cm Ϫ2 and 44-nm-thick Al 0.18 Ga 0.82 As barriers. The absorption spectrum of the grown structure, shown in Fig. 1, was performed using Fourier transform spectrometer with 1000 K blackbody radi...

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Section: Report Documentation Pagementioning

confidence: 92%

“…6.5-nm-thick Si-doped GaAs wells with nominal doping density of 1.1ϫ10 12 cm Ϫ2 and 44-nm-thick Al 0.18 Ga 0.82 As barriers. The absorption spectrum of the grown structure, shown in Fig.…”

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confidence: 99%

Direct measurement of population-induced broadening of quantum well intersubband transitions

Almogy

O’Brien

et al. 1997

Applied Physics Letters

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“…Dupont et al measured low-temperature linewidths in δ-doped GaAs/Al 0.25 Ga 0.75 As QWs with L = 76Å and N S ∼ 1×10 12 cm −2 for two different doping positions: Z = 0 and 112Å [10]. We calculate linewidth and transport broadening for the same structures.…”

Section: Doping Position Dependencementioning

confidence: 99%

“…To investigate the effects of various scattering processes, intersubband absorption linewidths have been measured for various temperatures [8], well widths [9], alloy compositions [9], and doping positions [10] in GaAs and other QWs. These results show that absorption linewidth has a weak dependence on temperature and alloy composition and apparently has little correlation with mobility.…”

Section: Introductionmentioning

confidence: 99%

Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impurities

Unuma

Yoshita

Noda

et al. 2003

Journal of Applied Physics

236

184

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We calculate the intersubband absorption linewidth 2Γop in quantum wells (QWs) due to scattering by interface roughness, LO phonons, LA phonons, alloy disorder, and ionized impurities, and compare it with the transport energy broadening 2Γtr = 2h/τtr, which corresponds to the transport relaxation time τtr related to the electron mobility µ. Numerical calculations for GaAs QWs clarify the different contributions of each individual scattering mechanism to the absorption linewidth 2Γop and transport broadening 2Γtr.Interface roughness scattering contributes about an order of magnitude more to the linewidth 2Γop than to the transport broadening 2Γtr, because the contribution from the intrasubband scattering in the first excited subband is much larger than that in the ground subband. On the other hand, LO phonon scattering (at room temperature) and ionized impurity scattering contribute much less to the linewidth 2Γop than to the transport broadening 2Γtr. LA phonon scattering makes comparable contributions to the linewidth 2Γop and transport broadening 2Γtr, and so does alloy disorder scattering.The combination of these contributions with significantly different characteristics makes the absolute values of the linewidth 2Γop and transport broadening 2Γtr very different, and leads to the apparent lack of correlation between them when a parameter, such as temperature or alloy composition, is changed. Our numerical calculations can quantitatively explain the previously reported experimental results.

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“…[1][2][3][4][5][6][7][8]. The effects of disorder on the IS absorption line have been investigated experimentally [9], however, detailed theory is still missing.…”

Section: Introductionmentioning

confidence: 99%

Effects of extreme disorder on electronic properties in δ-doped semiconductor microstructures—a realistic computer simulation

Metzner

Hofmann

Döhler

1999

Superlattices and Microstructures

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Influence of ionized impurities on the linewidth of intersubband transitions in GaAs/GaAlAs quantum wells

Cited by 41 publications

References 8 publications

Direct measurement of population-induced broadening of quantum well intersubband transitions

Direct measurement of population-induced broadening of quantum well intersubband transitions

Intersubband absorption linewidth in GaAs quantum wells due to scattering by interface roughness, phonons, alloy disorder, and impurities

Effects of extreme disorder on electronic properties in δ-doped semiconductor microstructures—a realistic computer simulation

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