The effect of Si doping on the electrical properties of B12As2 thin films on (0001) 6H-SiC substrates

Zong-ze, XU; Edgar, James H.; Baumann, S.; Bleiler, R. J.; Wang, S. H.; Mohney, Suzanne E.

doi:10.1063/1.2437687

Cited by 8 publications

(7 citation statements)

References 15 publications

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“…6,10 This effect has also been observed in B 12 P 2 films grown in our group, which may influence the electrical properties of the metal-semiconductor interface independently of any sintering effects. To decouple the effects of annealing-induced changes in the sheet resistance from the sintering of metal contacts, the B 12 P 2 films were annealed in Ar at 800 C for 30 s before any metal contacts were deposited.…”

Section: Experimental Methods and Processingsupporting

confidence: 72%

“…Recent advancements in the improved heteroepitaxial growth of a similar rhombohedral boride, B 12 As 2 , have been achieved on SiC, including suppression of double-position twinning 4,5 and control of p-type doping 6 (note: n-type conductivity in neither B 12 P 2 nor B 12 As 2 has been reported yet). Heterojunction pn-diodes of p-B 12 As 2 /n-SiC have also been demonstrated.…”

Section: Introductionmentioning

confidence: 99%

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Sintered Cr/Pt and Ni/Au ohmic contacts to B12P2

Frye

Kucheyev

Edgar

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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Icosahedral boron phosphide (B 12 P 2 ) is a wide-bandgap semiconductor possessing interesting properties such as high hardness, chemical inertness, and the reported ability to self-heal from irradiation by high energy electrons. Here, the authors developed Cr/Pt and Ni/Au ohmic contacts to epitaxially grown B 12 P 2 for materials characterization and electronic device development. Cr/Pt contacts became ohmic after annealing at 700 C for 30 s with a specific contact resistance of 2 Â 10 À4 X cm 2 , as measured by the linear transfer length method. Ni/Au contacts were ohmic prior to any annealing, and their minimum specific contact resistance was $l-4 Â 10 À4 X cm 2 after annealing over the temperature range of 500-800 C. Rutherford backscattering spectrometry revealed a strong reaction and intermixing between Cr/Pt and B 12 P 2 at 700 C and a reaction layer between Ni and B 12 P 2 thinner than $25 nm at 500 C. V C 2015 American Vacuum Society.

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Section: Experimental Methods and Processingsupporting

confidence: 72%

Section: Introductionmentioning

confidence: 99%

Sintered Cr/Pt and Ni/Au ohmic contacts to B12P2

Frye

Kucheyev

Edgar

et al. 2015

Journal of Vacuum Science &Amp; Technology A: Vacuum, Surfaces, and Films

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“…This occurs because inter-icosahedral bonding is maintained when an As atom is replaced by a vacancy or either a B, group IV, or group VI atom, and the resulting hole on the As site leads to p-type conductivity. 2 For example, Xu et al 14 demonstrated that the conductivity of high-resistivity p-type IBA epilayers grown on semi-insulating 6H-SiC could be effectively modulated by Si doping, resulting in p-type conduction with a Â 10 5 reduction in the resistivity. Hall effect measurements on similar as-grown epilayers (%3 lm thick) also exhibited p-type conductivity with hole concentrations 15 in the range (%10 13 -10 16 ) cm À3 .…”

Section: Introductionmentioning

confidence: 99%

Photoluminescence investigation of the indirect band gap and shallow impurities in icosahedral B12As2

Klein

Nwagwu

Edgar

et al. 2012

Journal of Applied Physics

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The indirect band gap of icosahedral B 12 As 2 (IBA) has been determined by variable temperature photoluminescence measurements (8 K-294 K) on solution-grown bulk samples. In addition, evidence of three shallow acceptor levels and one shallow donor level is reported. The lowtemperature spectra were characterized by broad and intense deep defect emission, donor-acceptor pair (DAP) bands, and exciton recombination. The appearance of DAP emission verifies the incorporation of a donor in IBA, which has not been reported previously. The temperature dependence of the free exciton (FE) intensity reflected a FE binding energy of 45 meV. The variation of the FE peak position with temperature was fitted with both Varshni and Pässler models to determine an expression for the temperature dependence of the indirect band gap. The resulting low and room temperature band gaps are E g (0) ¼ 3.470 eV and E g (294 K) ¼ 3.373 eV, respectively. The latter is not consistent with previous reports of the room temperature band gap, 3.20 eV and 3.47 eV, derived from band structure calculations and optical absorption, respectively. The origin of these discrepancies is discussed. The DAP spectra reveal three relatively shallow acceptors with binding energies of %175, 255, and 291 meV, and a shallow donor with binding energy %25 meV. Although the identity of the individual acceptors is not known, they appear to be associated with the light-hole band. The small donor binding energy is suggestive of an interstitial donor impurity, which is suspected to be Ni. V C 2012 American Institute of Physics.

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“…These atoms have higher electronegativity than that of boron. The resulting materials are B 4 C, B 12 P 2 , B 12 As 2 , and B 12 O 2 (B 4 C has a slightly different structure from the others), which have a wider band gap than α-rh boron according to the electronic structure calculations. − Their electrical conduction is also p-type. − A discussion of why these materials become p-type was presented by Emin based on the molecular orbital scheme . The hole doping to B 4 C, B 12 P 2 , and B 12 As 2 to achieve superconductivity was proposed by Calandra et al…”

Section: Introductionmentioning

confidence: 99%

Effect of Codoping in α-Rhombohedral Boron

Hayami

Otani

2008

J. Phys. Chem. C

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α-Rhombohedral (α-rh) boron is the most stable polymorph of elemental boron at low temperatures and exhibits p-type semiconductive properties. Although α-rh boron has some voids of sufficient size in its structure, it does not accept alkali metals as donor dopants. An n-type or metallic α-rh boronlike material so far has not been found. We considered substituting Li for either of P or As in the stable α-rh boronlike compounds B12P2 and B12As2 and calculated the electronic structures from first principles to investigate the possibility that α-rh boron becomes an n-type semiconductor or a metal. The idea is similar to the case of diamond, where the codoping of a donor and acceptor creates an n-type semiconductor. Our results showed that B12PLi and B12AsLi became intrinsic narrow-gap semiconductors with band gaps of 0.478 and 0.536 eV, respectively. In both materials, the curvature of the conduction band was higher than that of the valence band, suggesting that the electron mobility may be higher than the hole mobility.

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The effect of Si doping on the electrical properties of B12As2 thin films on (0001) 6H-SiC substrates

Cited by 8 publications

References 15 publications

Sintered Cr/Pt and Ni/Au ohmic contacts to B12P2

Sintered Cr/Pt and Ni/Au ohmic contacts to B12P2

Photoluminescence investigation of the indirect band gap and shallow impurities in icosahedral B12As2

Effect of Codoping in α-Rhombohedral Boron

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