Growth of single phase GaAs1−xNx with high nitrogen concentration by metal–organic molecular beam epitaxy

Qiu, Yn; Nikishin, S. A.; Temkin, H.; Faleev, N. N.; Kudriavtsev, Yu.

doi:10.1063/1.119137

Cited by 57 publications

(27 citation statements)

References 9 publications

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“…The same conclusion results if we consider the number of N atoms, N W , in a window of fixed size, and move that window over the alloy layer; we find fluctuations in the values of N W which equal, within a few %, the expected value of 18 ≈ where is the average value of NW [15]. Thus, we find no evidence for medium-or long-range compositional fluctuations of the N atoms, as has been suggested in some recent studies [4,7]. To model GaAsN alloys, at least of the type grown here, our results indicate that one can simply assume a modest ( %) enhancement of the number of second (and possibly also the first) nearest-neighbor pairs, together with a random distribution of all other pairs.…”

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confidence: 48%

“…Important applications include lasers with wavelength in the 1.3-1.55 µm range, as well as solar cells with band gap around 1.0 eV [3]. Generally speaking the GaAsN and InGaAsN alloys have displayed evidence of inhomogeneities, such as broad photoluminescence (PL) line widths, variable PL decay times, and short minority carrier diffusion lengths [4][5][6][7]. Such observations are often taken as an indicator of compositional fluctuations in the materials, although direct structural characterization of such fluctuations is lacking.…”

Section: Introductionmentioning

confidence: 99%

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Arrangement of nitrogen atoms in GaAsN alloys determined by scanning tunneling microscopy

McKay

Feenstra

Schmidtling

et al. 2001

Applied Physics Letters

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The pair distribution function of nitrogen atoms in GaAs0.983N0.017 has been determined by scanning tunneling microscopy. Nitrogen atoms in the first and third planes relative to the cleaved (1 0) surface are imaged. A modest enhancement in the number of nearest-neighbor pairs particularly with [001] orientation is found, although at larger separations the distribution of N pair separations is found to be random.Considerable interest has developed in recent years concerning GaAsN and InGaAsN alloys with low N content, typically a few %. The large predicted band gap bowing in this system of highly mismatched anions leads to the possibility of considerable band gap reduction with modest N content [1,2]. Important applications include lasers with wavelength in the 1.3-1.55 µm range, as well as solar cells with band gap around 1.0 eV [3]. Generally speaking the GaAsN and InGaAsN alloys have displayed evidence of inhomogeneities, such as broad photoluminescence (PL) line widths, variable PL decay times, and short minority carrier diffusion lengths [4][5][6][7]. Such observations are often taken as an indicator of compositional fluctuations in the materials, although direct structural characterization of such fluctuations is lacking.In this work we use cross-sectional scanning tunneling microscopy (STM) to directly probe the arrangement of N atoms in GaAs 0.983 N 0.017 alloys. Nitrogen atoms of two distinct contrast levels are imaged, which we assign to occupation in the first and third surface planes relative to the (1 0) surface. From an accurate determination of the position of about 1000 N atoms in a continuous strip of alloy material, we compute the distribution function of pair separations. The arrangement of N atoms is found to be quite consistent with that expected from random occupation, with the exception that an enhanced occurrence of nearest-neighbor N pairs is found.The GaAsN alloys studied here were grown on GaAs(001) substrates by metal organic vapor phase epitaxy (MOVPE) at temperatures between 530 and 570 C using TMGa, TBAs or AsH3, and tertiarybutylhydrazine (TBHy) under hydrogen carrier gas. Additional details of the growth and characterization of the material can be found in Ref. [8]. The particular film studied here consists of a GaAs buffer layer followed by a GaAs 0.983 N 0.017 layer, a 52 nm thick GaAs spacer layer, a GaAs 0.972 N 0.028 layer, and a 370 nm thick GaAs cap layer. The thickness of the GaAsN layers was determined by high-resolution x-ray diffraction (HRXRD) to be about 18 nm; STM measurements of their thickness gave results of 14-19 nm depending on location in the wafer. The N contents quoted above were also determined by HRXRD; STM measurements for those quantities gave similar results. The GaAs substrate, buffer layer, and cap layer were doped with Si at a con-1 1°P ublished in Appl. Phys. Lett. 78, 82 (2001).

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confidence: 48%

Section: Introductionmentioning

confidence: 99%

Arrangement of nitrogen atoms in GaAsN alloys determined by scanning tunneling microscopy

McKay

Feenstra

Schmidtling

et al. 2001

Applied Physics Letters

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“…However, while, on the As-rich side of the phase diagram, it is possible to incorporate up to ~10-15% of N into cubic GaAs [27,28], on the N-rich side not more than ~1% of As in GaN have been achieved [23][24][25][26]. In the intermediate region usually the coexistence of hexagonal N-rich GaAsN and cubic As-rich GaNAs phases is observed.…”

Section: Introductionmentioning

confidence: 99%

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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“…[26]. They determine b =-19 eV for the strained GaNAs layers [27] [28] with nitrogen concentration up to ~3%.…”

Section: Resultsmentioning

confidence: 99%

Optical Properties of GaNAs Grown by MBE

Pozina

Ivanov

Ḿonemar

et al. 1998

MRS Internet j. nitride semicond. res.

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Optical properties of the GaNxAs1−x layers grown on (001) GaAs substrates by molecular beam epitaxy have been studied. The samples can be classified into three categories with respect to the concentration of N, as determined by x-ray diffraction and secondary-ion mass spectrometry: (i) with doping nitrogen concentration, (ii) with average content of N less than 30 %, and (iii) with x close to 100 %. From optical measurements of photoluminescence and Raman scattering, combined with analysis of x-ray diffraction spectra, different phases are observed in the GaNxAs1−x layers: GaAs, GaN and the solid ternary solution GaNxAs1−x. We have estimated the fundamental band-gap energy in the GaNxAs1−x alloy with low nitrogen concentration (up to x = 0.04) from absorption measurements, and in GaNxAs1−x with low arsenic concentration (up to 1−x = 0.04) - from photoluminescence spectra. An analysis of the dependence of the experimental values of the GaNxAs1−x band-gap energy on the nitrogen composition indicates a constant bowing parameter b as large as b = -18 eV.

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Growth of single phase GaAs1−xNx with high nitrogen concentration by metal–organic molecular beam epitaxy

Cited by 57 publications

References 9 publications

Arrangement of nitrogen atoms in GaAsN alloys determined by scanning tunneling microscopy

Arrangement of nitrogen atoms in GaAsN alloys determined by scanning tunneling microscopy

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

Optical Properties of GaNAs Grown by MBE

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