Compensating point defects in<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mmultiscripts><mml:mi mathvariant="normal">He</mml:mi><mml:none /><mml:mo>+</mml:mo><mml:mprescripts /><mml:none /><mml:mn>4</mml:mn></mml:mmultiscripts></mml:math>-irradiated InN

Tuomisto, Filip; Pelli, A.; Yu, K. M.; Walukiewicz, W.; Schaff, William J.

doi:10.1103/physrevb.75.193201

Cited by 45 publications

(48 citation statements)

References 19 publications

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“…Details on the growth and characteristics of the samples can be found elsewhere. 6,7,18,19,36,37 Samples I and II show a strong change in the Doppler broadening signal when approaching the interface, which is a common feature in several previously investigated InN samples. 7,15,18,19 Therefore, the interface region is investigated separately in these two samples (see Sec.…”

Section: Experimental Spectra and Defect Identificationmentioning

confidence: 89%

“…An overview of a representative selection of measured samples is given in Table I. Sample I is MBE-grown material 6 which has been irradiated with 2-MeV He ions to a fluence of 8.9 × 10 15 cm −2 , samples II and III are as-grown Si-doped 36 and undoped 37 InN layers deposited by MBE and MOCVD, respectively. Details on the growth and characteristics of the samples can be found elsewhere.…”

Section: Experimental Spectra and Defect Identificationmentioning

confidence: 99%

“…17,20 In good agreement with the behavior of negatively charged defects below the branch point energy, 1,21 n-type doping of InN by either Si (Refs. 19 and 22) or high-energy particle irradiation 6 leads to an increasing incorporation of V In related defects, while Mg-doped samples (with lowered Fermi-level positions) show only low concentrations. 23 Unfortunately, the exact chemical identity of the vacancy defects detected in previous studies has remained largely unknown.…”

Section: Introductionmentioning

confidence: 99%

“…2 Intrinsic point defects have been accounted for multiple important mechanisms in the material. [3][4][5][6][7] Among them, isolated and complexed In vacancies (V In ) and N vacancies (V N ) are expected to be the dominant intrinsic acceptors and donors, respectively, according to latest density functional theory calculations. [8][9][10][11][12] Nevertheless, unambiguous experimental evidence on their nature and characteristics is still relatively scarce.…”

Section: Introductionmentioning

confidence: 99%

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Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

2011

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We present a comprehensive study of vacancy and vacancy-impurity complexes in InN combining positron annihilation spectroscopy and ab initio calculations. Positron densities and annihilation characteristics of common vacancy-type defects are calculated using density functional theory, and the feasibility of their experimental detection and distinction with positron annihilation methods is discussed. The computational results are compared to positron lifetime and conventional as well as coincidence Doppler broadening measurements of several representative InN samples. The particular dominant vacancy-type positron traps are identified and their characteristic positron lifetimes, Doppler ratio curves, and line-shape parameters determined. We find that indium vacancies (V In ) and their complexes with nitrogen vacancies (V N ) or impurities act as efficient positron traps, inducing distinct changes in the annihilation parameters compared to the InN lattice. Neutral or positively charged V N and pure V N complexes, on the other hand, do not trap positrons. The predominantly introduced positron trap in irradiated InN is identified as the isolated V In , while in as-grown InN layers V In do not occur isolated but complexed with one or more V N . The number of V N per V In in these complexes is found to increase from the near-surface region toward the layer-substrate interface.

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Section: Experimental Spectra and Defect Identificationmentioning

confidence: 89%

Section: Experimental Spectra and Defect Identificationmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

2011

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“…16 In this work, we investigate the magnetic properties of 3 lm-thick GaN layers grown by metal-organic chemical-vapor deposition (MOCVD) on sapphire substrates with point defects controllably created via high energy He irradiation, as measured by Tuomisto et al in Ref. 17. Three irradiated samples studied in this work cover a wide range of concentrations of the introduced Ga vacancies in the range 10 17 À10 19 cm À3 , while the vacancy concentrations are below the detection limit (10 16 cm À3 ) of positron annihilation spectroscopy in the non-irradiated reference.…”

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confidence: 99%

Magnetically active vacancy related defects in irradiated GaN layers

et al. 2012

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We present the studies of magnetic properties of 2 MeV 4He+-irradiated GaN grown by metal-organic chemical-vapor deposition. Particle irradiation allowed controllable introduction of Ga-vacancy in the samples. The magnetic moments with concentrations changing between 4.3...8.3x10^17 cm^-3 showing superparamagnetic blocking at room temperature are observed. The appearance of clear hysteresis curve at T = 5 K with coercive field of about H_C = 270 Oe suggests that the formation of more complex Ga vacancy related defects is promoted with increasing Ga vacancy content. The small concentration of the observed magnetically-active defects with respect to the total Ga- vacancy concentration suggests that the presence of the oxygen/hydrogen-related vacancy complexes is the source of the observed magnetic moments.Comment: 3 pages, 3 figure

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N‐type doping of InGaN by high energy particle irradiation

Yu¹

2009

Physica Status Solidi (a)

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This article reviews our extensive studies of the effects of native defects introduced by high energy particles on the electrical and optical properties of InGaN alloys. We show that the electronic properties of irradiated InGaN can be well described by the amphoteric defect model. Because of the extremely low position of the conduction band edge of InN the formation energy of native donor defects is very low in In‐rich InGaN alloys. High energy particle irradiation of InN and In‐rich InGaN, will therefore produce donor defects and result in more n‐type materials. As the irradiation dose increases, the electron concentration increases until the Fermi energy EF approaches the Fermi stabilization energy EFS. At this point both donor and acceptor‐type defects are formed at similar rates, and compensate each other, leading to stabilization of EF and a saturation of the electron concentration. Hence a large increase and then saturation in the Burstein–Moss shift of the optical absorption edge is also observed. Furthermore we also found that mobilities in the irradiated films can be well described by scattering from triply charged defects, providing strong evidence that native defects in InN are triple donors. The excellent agreement between the experimental results and predictions based on the ADM suggests that particle irradiation can be an effective and simple method to control the doping (electron concentration) in In‐rich Inx Ga1–x N via native point defects. (© 2009 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

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Compensating point defects inHe+4-irradiated InN

Cited by 45 publications

References 19 publications

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

Identifying vacancy complexes in compound semiconductors with positron annihilation spectroscopy: A case study of InN

Magnetically active vacancy related defects in irradiated GaN layers

N‐type doping of InGaN by high energy particle irradiation

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