Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy

Vaithianathan, V.; Lee, Byung‐Teak; Chang, Chang-Hwan; Asokan, K.; Kim, Sang Sub

doi:10.1063/1.2186383

Cited by 65 publications

(36 citation statements)

References 23 publications

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“…Unfortunately our experiments cannot settle the interesting issue whether substitutional As on oxygen sites (As O ), as is often assumed [3,4,8], or As Zn −2V Zn complexes, as was suggested by Limpijumnong et al [13,14], are responsible for the acceptor action in As-doped ZnO. The fact that implanted As prefers the substitutional Zn sites is clearly a strong argument in favor of the As Zn −2V Zn model.…”

Section: Relevance Of Current Results With Respect To the Acceptor Momentioning

confidence: 73%

“…In the case of the technologically promising II-VI compound ZnO, besides N [1,2] the heavy group-V elements P [1,2], As [2][3][4][5][6][7][8][9], and Sb [10][11][12] have been reported in the literature as possible p-type dopants. However, there is an ongoing debate whether for P, As, and Sb the p-type character results from these impuritities simply replacing O atoms, thus acting as simple "chemical" dopants [3,4,8], or is due to the formation of more complicated defect complexes [9,[12][13][14].…”

Section: Introductionmentioning

confidence: 99%

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Arsenic in ZnO and GaN: Substitutional Cation or Anion Sites?

et al. 2007

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We have determined the lattice location of ion implanted As in ZnO and GaN by means of conversion electron emission channeling from radioactive 73 As. In contrast to what one might expect from its nature as a group V element, we find that As does not occupy substitutional O sites in ZnO but in its large majority substitutional Zn sites. Arsenic in ZnO is thus an interesting example for an impurity in a semiconductor where the major impurity lattice site is determined by atomic size and electronegativity rather than its position in the periodic system. In contrast, in GaN the preference of As for substitutional cation sites is less pronounced and about half of the implanted As atoms occupy Ga and the other half N sites. Apparently, the smaller size-mismatch between As and N and the chemical similarity of both elements make it feasible that As partly substitutes for N atoms.

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Section: Relevance Of Current Results With Respect To the Acceptor Momentioning

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Arsenic in ZnO and GaN: Substitutional Cation or Anion Sites?

et al. 2007

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confidence: 99%

“…In order to explain the p-type character of ZnO following As and Sb doping it was suggested that the acceptor action is actually due to As Zn -2V Zn or Sb Zn -2V Zn complexes, where an As or Sb atom occupies a Zn "anti-site" and is decorated with two Zn vacancies [16][17][18][19]. However, a complex acceptor model for P, As or Sb in ZnO is strongly disputed by some authors [20][21][22][23][24].Obviously knowledge on the lattice location of the group V elements in ZnO is crucial in order to assess the related mechanism of p-type doping. We have previously determined the lattice sites of ion implanted As by means of conversion electron emission channeling from radioactive 73 As [25][26][27] and found that As does not occupy substitutional O sites but mostly substitutional Zn sites.…”

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confidence: 99%

Direct evidence for Sb as a Zn site impurity in ZnO

Wahl

Correia

Mendonça

et al. 2009

Applied Physics Letters

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The lattice location of ion implanted antimony in zinc oxide has been determined by means of β − emission channeling from the radioactive 124 Sb isotope. Following 30 keV implantation of 124 Sb into a single-crystalline ZnO sample to a fluence of 1×10 14 cm −2 , the angular-dependent emission rate of β − particles around several crystallographic directions was measured with a position-sensitive Si detector. The majority of Sb was found to occupy Zn sites, with the possible fraction on O sites being at maximum 5-6%. To date, the group V element antimony is one of the elements which have been used as p-type dopants in the II-VI semiconductor zinc oxide, the others being N, P and As (cf. Ref.[1] and Refs. therein). In the case of Sb, following the report of Sb-doped p-type ZnO by Aoki et al in 2002 [2] and further work by other authors [3][4][5][6], recently the realization of a wide range of optoelectronic devices incorporating pZnO:Sb layers have been reported, including homo-and heterojunction photodiodes [7][8], ultraviolet (UV) light emitting diodes (LEDs) [9][10][11][12], and UV lasers [13].While technological applications of p-type ZnO seem thus to have come within reach, the nature of the acceptors in P, As or Sb-doped ZnO continues to be disputed in the literature. From a simple viewpoint of chemical bonding, the substitution of O 2− cations in ZnO by P 3− , As 3− or Sb 3− should create fully ionized acceptors. However, due to the large mismatch of the ionic radii of P 3− (2.12 Å), As 3− (2.22 Å) and Sb 3− (2.45 Å) with the ionic radius of O 2− (1.38 Å) it was argued that those impurities should have a low solubility substituting for O [14]. Moreover, theory suggests that the energy levels of P, As and Sb replacing O are located deep in the band gap of ZnO [15][16]. In order to explain the p-type character of ZnO following As and Sb doping it was suggested that the acceptor action is actually due to As Zn -2V Zn or Sb Zn -2V Zn complexes, where an As or Sb atom occupies a Zn "anti-site" and is decorated with two Zn vacancies [16][17][18][19]. However, a complex acceptor model for P, As or Sb in ZnO is strongly disputed by some authors [20][21][22][23][24].Obviously knowledge on the lattice location of the group V elements in ZnO is crucial in order to assess the related mechanism of p-type doping. We have previously determined the lattice sites of ion implanted As by means of conversion electron emission channeling from radioactive 73 As [25][26][27] and found that As does not occupy substitutional O sites but mostly substitutional Zn sites. In this work we report on the lattice location of ion implanted radioactive 124 Sb (t 1/2 = 60.3 d) using β − emission channeling and we present direct experimental evidence that Sb preferentially occupies Zn sites. Emission channeling [28] is based on the fact that charged particles from nuclear decay (α, β − , β + , conversion electrons) experience channeling or blocking effects along major crystallographic axes and planes. The resulting anisotropic emission yield p...

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“…In the meantime, As-doped p-type ZnO has been produced by means of pulsed laser deposition 7,[9][10][11][12] , hybrid beam deposition 13,14 , evaporation and sputtering 15 , ion implantation 16,17 , radiofrequency (RF) magnetron sputtering 18 , and metal-organic chemical vapor deposition (MOCVD) 19 , and devices include ultraviolet (UV) 14,17 and visual-infrared light emitting diodes (LEDs) 19 . Succesful doping methods for P include excimer laser processing 8 , diffusion 20,21 , RF sputter deposition [22][23][24][25][26] , molecular beam epitaxy (MBE) 27 , MOCVD 28 , and laser ablation 29 .…”

Section: Introductionmentioning

confidence: 99%

Lattice location of the group V elements Sb, As, and P in ZnO

Wahl¹,

Correia

Mendonça³

et al. 2010

Oxide-Based Materials and Devices

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Modifying the properties of ZnO by means of incorporating antimony, arsenic or phosphorus impurities is of interest since these group V elements have been reported in the literature among the few successful p-type dopants in this technologically promising II-VI compound. The lattice location of ion-implanted Sb, As, and P in ZnO single crystals was investigated by means of the electron emission channeling technique using the radioactive isotopes 124 Sb, 73As and 33 P and it is found that they preferentially occupy substitutional Zn sites while the possible fractions on substitutional O sites are a few percent at maximum. The lattice site preference is understandable from the relatively large ionic size of the heavy mass group V elements. Unfortunately the presented results cannot finally settle the interesting issue whether substitutional Sb, As or P on oxygen sites or Sb Zn −2V Zn , As Zn −2V Zn or P Zn −2V Zn complexes (as suggested in the literature) are responsible for the acceptor action. However, the fact that the implanted group V ions prefer the substitutional Zn sites is clearly a strong argument in favour of the complex acceptor model, while it discourages the notion that Sb, As and P act as simple "chemical" acceptors in ZnO.

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Characterization of As-doped, p-type ZnO by x-ray absorption near-edge structure spectroscopy

Cited by 65 publications

References 23 publications

Arsenic in ZnO and GaN: Substitutional Cation or Anion Sites?

Arsenic in ZnO and GaN: Substitutional Cation or Anion Sites?

Direct evidence for Sb as a Zn site impurity in ZnO

Lattice location of the group V elements Sb, As, and P in ZnO

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