Distinction between electron and hole traps in semi-insulating GaAs

Kiliulis, R.; Kažukauskas, V.; Bourgoin, J. C.

doi:10.1063/1.361520

Cited by 7 publications

(3 citation statements)

References 18 publications

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“…Fig.4 shows the TSC and TSHV spectra taken after 100sec exposure(during PQ) with of 1.16eV light. By comparing the TSHV and TSC spectra, we observe, (i) the metastable TSC peaks at 26K and 140K are present in TSHV spectra and hence these are hole traps [13], (ii) the TSC peaks at 65K, 90K and 120K are absent, instead a dip at their positions and these should be due to electron traps [13], which should give rise to negative peak in TSHV spectra.…”

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confidence: 92%

“EL2” revisited: Observation of metastable and stable energy levels of EL2 in semi-insulating GaAs

Kabiraj

Ghosh

2005

Applied Physics Letters

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By using combination of detailed experimental studies, we identify the metastable and stable energy levels of EL2 in semi-insulating GaAs. These results are discussed in the light of the recently proposed models for stable and metastable configurations of EL2 in GaAs. PACS numbers: 71.55.Eq, 72.80.Ey, 78.55.Cr Physics of metastable point defects is one of the most fascinating problems in contemporary condensed matter physics. Over the years several metastable defects in both covalent and ionic solids have been discovered, but for technological reasons, EL2 in GaAs is the most intensely studied, yet least understood, metastable defect. It is believed[1] that bond-breaking mechanism(BBM), in which defects change lattice position is universally responsible for all the metastable defects in solids. The EL2 defects[2], responsible for semi-insulating(SI) properties of GaAs by compensating residual acceptors, can exists in two different atomic configurations. The first one is the well characterized normal configuration(EL2 n ) and the second one is the metastable configuration(EL2 m ) in which all the optical, electrical and magnetic properties of EL2 disappear when SI-GaAs is illuminated with a subband gap light ∼1.1eV at low temperature(≤150K), known as phtoquenching(PQ). EL2 m is metastable because all the properties can be recovered either by heating the sample, or by phtoexcitation at low temperature, known as photorecovery(PR). Though, a great deal of attention has already been paid to understand the physics of this defect, but the microscopic origin of EL2 remains illusive till today. In particular, the most important issues remained to be resolved are, (i) atomic configuration of EL2 in both normal and metastable configurations, (ii) driving mechanism for EL2 n to EL2 m transition and, (iii) compensation mechanism after PQ, since free holes with concentration same as that of EL2 will be available when EL2s are in photoquenched state. There are some efforts [3,4,5,6] to explain some of these issues by postulating the existence of actuator levels which trigger the metastable transition by capturing photoexcited holes from EL2s. But, this actuator level is characterized by the absence of any direct experimental observation. In addition to this, interest in EL2 has been revived for two reasons, first: an increasing interest in defect engineering using this defect and second: the role of this defect on the properties of low temperature grown GaAs.Several models[2] based on either isolated native point defect or defect complex comprising of arsenic anitisite(As Ga ), gallium antisite(Ga As ), arsenic vacancy(V Aa ), gallium vacancy(V Ga ), arsenic interstitial(As i ) have been proposed, but very little is known about the electrical properties and defect energy levels of EL2 m . Recently, two models, for the first time, proposed correlation between electrical activity and the defect energy level related to metastable configuration of EL2. Fukuyama et al [7] have proposed a BBM-based model and shown that a three-cen...

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confidence: 92%

“EL2” revisited: Observation of metastable and stable energy levels of EL2 in semi-insulating GaAs

Kabiraj

Ghosh

2005

Applied Physics Letters

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“…residual donors (usually Si) and shallow carbon acceptors which are intentionally introduced in GaAs at the level of n C $ 0:5 Â 10 15 cm À3 . However, thermally stimulated (TS) current in conjunction with TS Hall effect measurements [14] have demonstrated that the concentration of the deep hole traps in SI-GaAs is of the same order as the concentration of the deep electron traps, and that the pinning of the Fermi level on the EL2 midgap may be explained as a result of the balance between deep electron and hole traps. The capture of electrons by the EL2 þ traps occurs over a configuration barrier with energy of $0:066 eV [15].…”

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confidence: 99%

Electric-Field-Enhanced Neutralization of Deep Centers in GaAs

et al. 2009

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The charge dynamics of hydrogenlike centers in semi-insulating GaAs have been studied by muon spin resonance in the presence of electric field and RF excitation. Electric-field-enhanced neutralization of deep electron and hole traps by track-induced hot carriers results in an increase of the excess electron's or hole's lifetimes. Similar processes may take place in semiconductor devices working at high voltages and/or under irradiation. As a consequence of the deep traps neutralization, the muonium (mu{+} + e{-}) center can capture a hole.

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“…However, the Fermi level (EF) is often found to lie below the EL2 midgap level, implying the existence of deep acceptor defects which can act like hole traps. Thermally stimulated (TS) current in conjunction with TS Hall effect measurements [14] have demonstrated that the concentration of the deep hole traps in SI-GaAs is of the same order as the concentration of the deep electron traps, and that the pinning of the Fermi level on the EL2 midgap may be explained as a result of the balance between deep electron and hole traps. The capture of electrons by the EL2 + traps occurs over a configuration barrier with energy of ∼ 0.066 eV [15].…”

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The microscopic study of a single hydrogen-like impurity in semi-insulating GaAs

Eshchenko,

Storchak,

Cottrell

et al. 2008

Preprint

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The charge dynamics of hydrogen-like centers formed by the implantation of energetic (4 MeV) muons in semi-insulating GaAs have been studied by muon spin resonance in electric fields. The results point to the significant role of deep hole traps in the compensation mechanism of GaAs. Electric-field-enhanced neutralization of deep electron and hole traps by muon-track-induced hot carriers results to an increase of the non-equilibrium carrier life-times. As a consequence, the muonium (µ + + e − ) center at the tetrahedral As site can capture the track's holes and therefore behaves like a donor.

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Distinction between electron and hole traps in semi-insulating GaAs

Cited by 7 publications

References 18 publications

“EL2” revisited: Observation of metastable and stable energy levels of EL2 in semi-insulating GaAs

“EL2” revisited: Observation of metastable and stable energy levels of EL2 in semi-insulating GaAs

Electric-Field-Enhanced Neutralization of Deep Centers in GaAs

The microscopic study of a single hydrogen-like impurity in semi-insulating GaAs

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