Some recent advances in ab initio calculations of nonradiative decay rates of point defects in semiconductors

Wang, Lin‐Wang

doi:10.1088/1674-4926/40/9/091101

Cited by 11 publications

(11 citation statements)

References 36 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…Our first-principles calculations of electronic structure and total energy are carried out using spin-polarized density-functional theory (DFT), as implemented in the PWmat package, with the NCPP-SG15-PBE pseudopotentials − for the exchange-correlation functional. To improve the accuracy of the total energy and electronic band structure, the Heyd–Scuseria–Ernzerhof (HSE06) hybrid functional method with a mixing parameter of 50% is employed.…”

Section: Methodsmentioning

confidence: 99%

“…According to static coupling approximation, , the electron–phonon coupling constant can be obtained within one self-consistent field calculation. ,, Then, the nonradiative decay probability ( W ij ) can be calculated by the first-principles method: W i j = true( π k T λ true) 1 / 2 ( ∑ k 1 ω k 2 | C i , j k | 2 ) .25em exp [ − true( E i − E j − λ true) 2 4 k T λ ] where C i , j k is the electron–phonon coupling constant between electronic states i and j , as well as phonon mode k . λ is the reorganization energy (structural relaxation energy between initial and final configurations after the charge state transition from i to j ).…”

Section: Methodsmentioning

confidence: 99%

“…The defect transition level ε α (q/q′) is defined as the Fermi level (E F ), at which the formation energy for defect with charge state q and q′ are equal, that is According to static coupling approximation, 30,31 the electron−phonon coupling constant can be obtained within one self-consistent field calculation. 23,32,33 Then, the nonradiative decay probability (W ij ) can be calculated by the firstprinciples method: 34…”

Section: ■ Methodsmentioning

confidence: 99%

See 2 more Smart Citations

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Qiu,

Song,

Deng

et al. 2023

J. Am. Chem. Soc.

View full text Add to dashboard Cite

The conventional single-defect-mediated Shockley−Read−Hall model suggests that the nonradiative carrier recombination rate in wide-band gap (WBG) semiconductors would be negligible because the single-defect level is expected to be either far from valence-band-maximum (VBM) or conduction-band-minimum (CBM), or both. However, this model falls short of elucidating the substantial nonradiative recombination phenomena often observed experimentally across various WBG semiconductors. Owing to more localized nature of defect states inherent to WBG semiconductors, when the defect charge state changes, there is a pronounced structural relaxation around the local defect site. This suggests that a defect at each charge state may exhibit a few distinct local configurations, namely, a stable configuration and a few metastable/transit state configurations. Consequently, a dual-level nonradiative recombination model should more realistically exist in WBG semiconductors. In this model, through the dual-level mechanism, electron and hole trap levels are different from each other and could be closer to the CBM for the electron trap and closer to the VBM for the hole trap, respectively; therefore, this significantly increases the corresponding electron and hole capture rates, enhancing the overall process of nonradiative recombination, and explains the experimental observations. In this work, taking technically important SiO 2 as an illustrative example, we introduce the dual-level mechanism to elucidate the mechanism of nonradiative carrier recombination in WBG semiconductors. Our findings demonstrated strong alignment with available experimental data, reinforcing the robustness of our proposed dual-level model. Our fundamental understanding, therefore, provides a clear physical picture of the issue and can also be applied to predict the defect-related nonradiative carrier recombination characteristics in other WBG materials.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: ■ Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Qiu,

Song,

Deng

et al. 2023

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…[ 38–40 ] If the occupancies of the phonon modes are n and m respectively for the corresponding initial and final states,

Ψ_{i, n} (r, R)

and

Ψ_{f, m} (r, R)

, the nonradiative decay probability

W_{i f}

is then given by the Fermi golden rule. [ 34,41,42 ]

W_{i f} = \frac{2 π}{ℏ} \sum_{n} \sum_{m} p (i, n) {false| V_{i n, f m} false|}^{2} δ (E_{i n} - E_{f m})

where

V_{i n, f m} = ⟨ Ψ_{f, m} (r, R) | H {|Ψ}_{i, n} (r, R) ⟩

are the off‐diagonal matrix elements of the Hamiltonian H and

p (i, n)

is the probability of the initial vibrational modes n in the given electronic state i .

p (i, n) = \frac{exp false(- E_{i n} / k_{normalB} T false)}{\sum_{n} exp false(- E_{i n} / k_{normalB} T false)}

…”

Section: Methodsmentioning

confidence: 99%

Directly Confirming the Z_1/2 Center as the Electron Trap in SiC Through Accessing the Nonradiative Recombination

Shi

Luo

et al. 2021

Physica Rapid Research Ltrs

View full text Add to dashboard Cite

SiC is an important wide‐bandgap semiconductor for high‐power electronics and high‐temperature applications. Its Z 1/2 center, recognized as a carrier lifetime killer, has been extensively studied as it is a key issue impeding many applications of SiC. It is well established that the Z 1/2 center originates from carbon vacancies (VC), but direct access to the microscopic mechanism underlying its nonradiative recombination process is lacking. Herein, to consolidate such identification, the multiphonon‐assisted nonradiative recombination rates of previously proposed different candidates of the Z 1/2 center are evaluated by performing first‐principles calculations. The calculated electron transition cross sections of the VC ( σ normaln = 2.5 × 10 − 15 cm 2 at the k‐site and σ normaln = 3.4 × 10 − 15 cm 2 at the h‐site) are in accordance with the experimental values [from σ normaln = 3.0 × 10 − 15 cm 2 to σ normaln = 1.0 × 10 − 14 cm 2 ] for the Z 1/2 center. However, all of the other candidates are orders of magnitudes smaller in transition cross sections. This provides further evidence that the carbon vacancy (VC) is the Z 1/2 center from the electron transition cross sections. However, it is also found that the hole transition cross sections of the VC are very small. Various hypotheses are provided to consolidate this fact with the conclusion that Z 1/2 is the carrier lifetime killer.

show abstract

“…The carrier capture is a multi-phonon assisted electronic transition process. [154][155][156] The capture rate can be computed from DFT calculations, [157] and used to identify detrimental defects. [158,159] The key issue here is the calculation of electron-phonon coupling matrix for a large supercell containing defects.…”

Section: Defect Propertiesmentioning

confidence: 99%

Advances and challenges in DFT-based energy materials design

Kang¹,

Xie²,

Wei³

2022

Chinese Phys. B

View full text Add to dashboard Cite

The growing worldwide energy needs call for developing novel materials for energy applications. Ab initio density functional theory (DFT) calculations allow the understanding and prediction of material properties at the atomic scale, thus, play an important role on the energy materials design. Due to the fast progress of computer power and development of calculation methodologies, DFT-based calculations have greatly improved its predictive power, and are now leading to a paradigm shift towards theory-driven materials design. The aim of this perspective is to introduce the advances in DFT calculations which accelerate energy materials design. We first present state-of-the-art DFT methods for accurate simulation of various key properties of energy materials. Then we show examples of how these advances lead to the discovery of new energy materials for photovoltaic, photocatalytic, thermoelectric, and battery applications. The challenges and future research directions in computational design of energy materials are highlighted at the end.

show abstract

Some recent advances in ab initio calculations of nonradiative decay rates of point defects in semiconductors

Cited by 11 publications

References 36 publications

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Directly Confirming the Z_1/2 Center as the Electron Trap in SiC Through Accessing the Nonradiative Recombination

Advances and challenges in DFT-based energy materials design

Contact Info

Product

Resources

About

Some recent advances in ab initio calculations of nonradiative decay rates of point defects in semiconductors

Cited by 11 publications

References 36 publications

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO2

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO2

Directly Confirming the Z1/2 Center as the Electron Trap in SiC Through Accessing the Nonradiative Recombination

Advances and challenges in DFT-based energy materials design

Contact Info

Product

Resources

About

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Dual-Level Enhanced Nonradiative Carrier Recombination in Wide-Gap Semiconductors: The Case of Oxygen Vacancy in SiO₂

Directly Confirming the Z_1/2 Center as the Electron Trap in SiC Through Accessing the Nonradiative Recombination