Magneto-optical and ODEPR investigations of native defects in substrate-free LT-MBE grown GaAs

Tkach, Igor; Steen, C.; Kiesel, P.; Spaeth, J.‐M.

doi:10.1016/s0921-4526(01)00800-6

Cited by 5 publications

(6 citation statements)

References 16 publications

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“…In LT-MBE GaAs, the gallium vacancies V Ga play the major role as acceptors. 7,8 This defect is known as a deep triple acceptor. 17 According to Krambrock et al, 3 for a LT-MBE sample grown at 200°C, 6% of the As Ga density is in the form of As Ga ϩ and becomes only 2% for a sample grown at 300°C.…”

Section: Discussionmentioning

confidence: 99%

“…3 SI samples have been widely studied due to technological 4 and scientific 5 interests. The main intrinsic deep defects in nonstoichiometric ͑As-rich͒ LT-MBE GaAs are arsenic antisites (As Ga ) 6,7 ͑midgap donors͒, arsenic interstitials (As i ) 6,7 ͑deep donors͒, gallium vacancies (V Ga ) 8,9 ͑deep acceptors͒, or combinations of them. 5,7 The most important intrinsic defect for the electrical characteristics of GaAs is the arsenic antisite (As Ga ), which can reach very high concentrations ͑up to 10 20 cm Ϫ3 ) and introduces a wellknown midgap level.…”

Section: Introductionmentioning

confidence: 99%

“…The main intrinsic deep defects in nonstoichiometric ͑As-rich͒ LT-MBE GaAs are arsenic antisites (As Ga ) 6,7 ͑midgap donors͒, arsenic interstitials (As i ) 6,7 ͑deep donors͒, gallium vacancies (V Ga ) 8,9 ͑deep acceptors͒, or combinations of them. 5,7 The most important intrinsic defect for the electrical characteristics of GaAs is the arsenic antisite (As Ga ), which can reach very high concentrations ͑up to 10 20 cm Ϫ3 ) and introduces a wellknown midgap level. Optical transition measurements 10 involving the neutral ground state (As Ga 0 ) and its first ionized state (As Ga ϩ ) show a transition energy around 0.645 eV.…”

Section: Introductionmentioning

confidence: 99%

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Reduction of variable range hopping conduction in low-temperature molecular-beam epitaxy GaAs

Albuquerque

Oliveira

Silva

et al. 2004

Journal of Applied Physics

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Studying the transport properties via Hall and resistivity measurements of low-temperature molecular-beam epitaxy (LT-MBE) GaAs samples, the optimal conditions for fabricating high-resistivity material are found. We present results on three LT-MBE GaAs samples grown at 215, 265, and 315 °C. The measurements were carried out at temperatures ranging from 130 to 300 K, and the hopping conduction mechanism in this range is identified as variable range hopping. The sample grown at 315 °C presents the highest hopping parameter; this appears to be due to a reduction in the density of hopping centers. The mechanisms responsible for this are discussed.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Reduction of variable range hopping conduction in low-temperature molecular-beam epitaxy GaAs

Albuquerque

Oliveira

Silva

et al. 2004

Journal of Applied Physics

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“…In semi-insulating GaAs, VRH occurs through the deep level defects originated during the low-temperature growth [12]. The main intrinsic deep defects in such As-rich lowtemperature MBE GaAs are arsenic anti-sites (As Ga ) [13,14] which are mid-gap donors that act as traps to the free carriers. The deep level defect density can be tuned by the temperature growth control.…”

Section: Introductionmentioning

confidence: 99%

Conduction mechanisms on annealed semi-insulating GaAs samples

Peres¹,

Chaves²,

Rubinger³

et al. 2011

Semicond. Sci. Technol.

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We have measured electrical resistivity in the range of 100-500 K on six semi-insulating low-temperature grown molecular-beam epitaxy GaAs samples that were exposed to annealing treatment. Samples 2, 3, 4, 5 and 6 were annealed with temperatures of 350 • C, 400 • C, 450 • C, 500 • C and 550 • C, while sample 1 was not exposed to the annealing process. We used the differential activation energy method to precisely identify the temperature region where the different conduction regimes dominate, i.e. band conduction, nearest neighbor hopping and variable range hopping. We will also show that the change on the density of states in the impurity band caused by annealing significantly alters the conduction mechanisms present in those samples.

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“…10 and 11͒ ͑deep acceptors͒, or combinations of them. 8 At room temperature the GaAs samples are SI due to trapping processes in As Ga and the most important recombination process is phonon assisted. Another characteristic of the recombination process is a fully nonradiative multiphonon emission process.…”

Section: Introductionmentioning

confidence: 99%

Blockade of free carriers by hopping carriers leading to the low-frequency current oscillations in semi-insulating GaAs

et al. 2006

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Semi-insulating GaAs samples show low-frequency current oscillations ͑LFO͒ under high dc voltage. These spontaneous oscillations are caused by traveling high-electric-field domains and can be explained based on the well-accepted model of electron trapping in deep levels by multiphonon emission processes. This paper aims to explain today the most important open question about LFO, namely, the cause of the very slow propagation of the domain resulting in the low frequencies. Our claim is that hopping conduction acts as a low mobility barrier for the free carriers leading to the formation of the electric-field domains. The barrier blocks, through a Coulomb shield, the flow of the high mobility free carriers leading to a charge accumulation, which produces the current pulse in the external circuit when the domain reaches the anode where it is destroyed. LFO occurs, therefore, only in the regime of band and hopping mixed conduction mechanisms.

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Magneto-optical and ODEPR investigations of native defects in substrate-free LT-MBE grown GaAs

Cited by 5 publications

References 16 publications

Reduction of variable range hopping conduction in low-temperature molecular-beam epitaxy GaAs

Reduction of variable range hopping conduction in low-temperature molecular-beam epitaxy GaAs

Conduction mechanisms on annealed semi-insulating GaAs samples

Blockade of free carriers by hopping carriers leading to the low-frequency current oscillations in semi-insulating GaAs

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