Suppression of phonon‐mediated hot carrier relaxation in type‐II InAs/AlAsxSb1 − x quantum wells: a practical route to hot carrier solar cells

Esmaielpour, Hamidreza; Whiteside, Vincent R.; Tang, Jinfeng; Vijeyaragunathan, S.; Mıshıma, Tetsuya D.; Cairns, Shayne; Santos, M. B.; Wang, Bin; Sellers, Ian R.

doi:10.1002/pip.2763

Cited by 42 publications

(44 citation statements)

References 38 publications

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“…In silicon colloidal quantum dots, the presence of hot carriers sustained (even) at low excitations levels was attributed to the indirect band gap of silicon, which served to increase the radiative recombination lifetime of photogenerated carriers. Similar effects have also recently been observed in InAs/AlAsSb QWs 25 .…”

Section: Introductionsupporting

confidence: 84%

“…In this regime, the long electron lifetime results in hot-carrier stability by inhibiting hot-electron thermalization 24,25 . The normalized PL spectra at T = 150 K (black line), 225 K (red line), and 300 K (green line) are shown in Fig.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…The PL can be modeled via a generalized Planck radiation law 30,31 :where, is the emitted photon energy, A is the absorptivity, Δ μ is the chemical potential or quasi-Fermi-level separation under laser excitation, and T C represents the non-equilibrium hot carrier temperature. In the simplest case, taking a linear fit to the high-energy tail of the natural logarithm of a PL spectrum determines the carrier temperature 14,15,24,25,32 . However, such an analysis can be problematic in the case of QWs, where higher carrier excitation (increased laser excitation) and/or increased temperature results in the redistribution and thermal occupation of carriers in the higher energy subbands of the QW 31,33 .…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…An advantage of the InAs/AlAs x Sb 1− x MQWs investigated here, is that the combination of large energy band offsets and relatively narrow QWs (2.4 nm) leads to a large ground to first excited subband separation (~0.7 eV) 24,25 . This is much greater than the PL linewidth therefore, any excited state broadening due to electrons can be discounted.…”

Section: Experimental Results and Analysismentioning

confidence: 99%

“…Recently, it was proposed that type-II QWs have the potential to inhibit hot-carrier relaxation much more strongly than conventional type-I QWs 24,25 . This mechanism was also observed in silicon colloidal quantum dots 26 , where perturbed hot-carrier relaxation was attributed to a decoupling of the phonons through the spatial separation of photogenerated carriers.…”

Section: Introductionmentioning

confidence: 99%

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Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling

Esmaielpour¹,

Whiteside²,

Piyathilaka³

et al. 2018

Sci Rep

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Hot electrons established by the absorption of high-energy photons typically thermalize on a picosecond time scale in a semiconductor, dissipating energy via various phonon-mediated relaxation pathways. Here it is shown that a strong hot carrier distribution can be produced using a type-II quantum well structure. In such systems it is shown that the dominant hot carrier thermalization process is limited by the radiative recombination lifetime of electrons with reduced wavefunction overlap with holes. It is proposed that the subsequent reabsorption of acoustic and optical phonons is facilitated by a mismatch in phonon dispersions at the InAs-AlAsSb interface and serves to further stabilize hot electrons in this system. This lengthens the time scale for thermalization to nanoseconds and results in a hot electron distribution with a temperature of 490 K for a quantum well structure under steady-state illumination at room temperature.

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Section: Introductionsupporting

confidence: 84%

Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Experimental Results and Analysismentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling

Esmaielpour¹,

Whiteside²,

Piyathilaka³

et al. 2018

Sci Rep

Self Cite

View full text Add to dashboard Cite

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Effect of occupation of the excited states and phonon broadening on the determination of the hot carrier temperature from continuous wave photoluminescence in InGaAsP quantum well absorbers

Esmaielpour

Whiteside

Hirst

et al. 2017

Progress in Photovoltaics

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An InGaAsP quantum well with a type‐II band alignment is studied using continuous wave power and temperature dependent photoluminescence (PL) spectroscopy. The small energy separation between the ground state and first excited state results in significant thermal carrier redistribution and excited state occupation, particularly, with increasing excitation power and temperature. This state filling is evident as a high‐energy shoulder in the PL spectra, the same energy region where in the simplest Planck‐description the gradient is considered inversely proportional to carrier temperature. The outcome of an excited state occupation in broadening the high‐energy PL tail is to perturb the temperature extracted using this analysis; therefore, the true temperature of carriers is not properly evaluated when significant state filling occurs. In addition, broadening of the PL due to phonons at higher temperatures also distorts (or falsely increases) the non‐equilibrium “hot” carrier temperature and as such should be considered when using Planck's relation. The role of these two effects is considered and their mutual effect on the analysis of the extracted hot carrier temperature discussed. Copyright © 2017 John Wiley & Sons, Ltd.

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The effects of intraband and interband carrier‐carrier scattering on hot‐carrier solar cells: A theoretical study of spectral hole burning, electron‐hole energy transfer, Auger recombination, and impact ionization generation

Tsai

2019

Progress in Photovoltaics

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The effects of carrier‐carrier scattering resulting from the Coulomb‐potential interaction between two electrons on hot‐carrier solar cells are theoretically studied. Theoretical models and explicit formulas for calculating intraband carrier‐carrier scattering rates, electron‐to‐hole energy transfer rates, Auger recombination rates, and impact ionization generation rates are presented and derived. The numerical calculations from these formulas are obtained, and their effects on hot‐carrier solar cells are investigated. Several findings can be concluded from this study: (1) Intraband electron‐electron scattering and hole‐hole scattering are normally fast enough to randomize carrier distribution in the momentum space and thus maintain quasiequilibrium to establish electron and hole temperatures at a steady state; (2) spectral hole burning in hot‐carrier solar cells can be incurred by fast carrier extraction processes through energy‐selective contacts and slow intraband carrier‐carrier scattering; (3) energy transfer between electrons and holes via intraband electron‐hole scattering cannot guarantee that electrons and holes will maintain the same carrier temperature for hot‐carrier solar cells in all cases, especially if the difference between electron and hole temperatures is smaller than 100 K; and (4) materials with a band‐gap energy larger than 1 eV are favorable as conventional solar cells in which Auger recombination is not significant. On the contrary, materials with a band‐gap energy smaller than 0.5 eV are not suitable for conventional solar cells due to the detrimental effects of Auger recombination. However, they are ideal materials for realizing hot‐carrier solar cells due to beneficial effects of impact ionization generation, although these beneficial effects can be undermined by spectral hole burning.

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Suppression of phonon‐mediated hot carrier relaxation in type‐II InAs/AlAs_xSb_{1 − x} quantum wells: a practical route to hot carrier solar cells

Cited by 42 publications

References 38 publications

Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling

Enhanced hot electron lifetimes in quantum wells with inhibited phonon coupling

Effect of occupation of the excited states and phonon broadening on the determination of the hot carrier temperature from continuous wave photoluminescence in InGaAsP quantum well absorbers

The effects of intraband and interband carrier‐carrier scattering on hot‐carrier solar cells: A theoretical study of spectral hole burning, electron‐hole energy transfer, Auger recombination, and impact ionization generation

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