Time-resolved studies of photoluminescence in GaNxP1−x alloys: Evidence for indirect-direct band gap crossover

Buyanova, Irina; Pozina, Galia; Bergman, J. P.; Chen, Weimin; Xin, H. P.; Tu, C. W.

doi:10.1063/1.1491286

Cited by 87 publications

(64 citation statements)

References 13 publications

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“…[9][10][11][12] Incorporation of several percent of nitrogen in gallium phosphide reduces its lattice constant, thereby minimizing lattice mismatch with Si. 13 Also, a strong interaction between the N-related localized states and the extended states of GaP modifies the band structure of the forming alloy leading to an increased oscillator strength of the band-to-band optical transitions [14][15][16] and a splitting of the conduction band states into two subbands. 15,17 The former is advantageous for utilizing this material in amber light emitting diodes, whereas the latter makes GaNP an attractive material for applications in innovative intermediate-band solar cells with an anticipated high efficiency.…”

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confidence: 99%

Raman spectroscopy of GaP/GaNP core/shell nanowires

Dobrovolsky

Sukrittanon²,

Kuang

et al. 2014

Applied Physics Letters

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Raman spectroscopy is employed to characterize structural and phonon properties of GaP/GaNP core/shell nanowires (NWs) grown by molecular beam epitaxy on Si substrates. According to polarization-dependent measurements performed on single NWs, the dominant Raman modes associated with zone-center optical phonons obey selection rules in a zinc-blende lattice, confirming high crystalline quality of the NWs. Two additional modes at 360 and 397 cm(-1) that are specific to the NW architecture are also detected in resonant Raman spectra and are attributed to defect-activated scattering involving zone-edge transverse optical phonons and surface optical phonons, respectively. It is concluded that the formation of the involved defect states are mainly promoted during the NW growth with a high V/III ratio.

Funding Agencies|Vetenskapsradet (Swedish Research Council) [621-2010-3815]; U.S. National Science Foundation [DMR-0907652, DMR-1106369]; Royal Government of Thailand Scholarship

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confidence: 99%

Raman spectroscopy of GaP/GaNP core/shell nanowires

Dobrovolsky

Sukrittanon²,

Kuang

et al. 2014

Applied Physics Letters

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Funding Agencies|Vetenskapsradet (Swedish Research Council) [621-2010-3815]; U.S. National Science Foundation [DMR-0907652, DMR-1106369]; Royal Government of Thailand Scholarship

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“…Also, a strong anticrossing interaction between the band states and nitrogen states leads to the giant bowing in the bandgap energy [9,10] and transforms the band gap character from an indirect bandgap in GaP to a quasi-direct band one in GaNP [10,11]. This increases light emission efficiency of the alloy and allows one to tune its band gap energy from Also, alloying with nitrogen allows one to realize nano-scale light sources that emit light linearly polarized perpendicularly to the wire axis even in zinc blende nanowires of various diameters [16].…”

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confidence: 99%

Optimizing GaNP Coaxial Nanowires for Efficient Light Emission by Controlling Formation of Surface and Interfacial Defects

et al. 2014

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We report on identification and control of important non-radiative recombination centers in GaNP coaxial nanowires (NWs) grown on Si substrates, in an effort to significantly increase light emitting efficiency of these novel nanostructures promising for a wide variety of 2 optoelectronic and photonic applications. A point defect complex, labeled as DD1 and consisting of a P atom with a neighboring partner aligned along a crystallographic <111> axis, is identified by optically detected magnetic resonance as a dominant non-radiative recombination center that resides mainly on the surface of the NWs and partly at the hetero-interfaces. The formation of DD1 is found to be promoted by the presence of nitrogen and can be suppressed by reducing the strain between the core and shell layers, as well as by protecting the optically active shell by an outer passivating shell. Growth modes employed during the NW growth are shown to play a role.Based on these results, we identify the GaP/GaN y P 1-y /GaN x P 1-x (x

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“…This is in agreement with our earlier time-resolved PL study of GaNP alloys by using ultrafast laser spectroscopy, from which the rise and decay times were determined to be in the range of 1 and 150 ns, respectively. 5 Equally fast rise and decay were also observed when P1 is switched on and off in the presence of cw P2 excitation, see the region I of the experimental curve in Fig. 5.…”

Section: Dynamics Of the Trapping And Photo-induced De-trapping Prmentioning

confidence: 90%

“…Alloying of gallium phosphide (GaP) with nitrogen (N) leads to a giant bandgap bowing [1][2][3][4] and N-induced transformation from an indirect to a quasi-direct bandgap, 4,5 largely improving radiative efficiency. Further alloying with In, resulting in GaInNP, adds additional freedom in bandgap and strain engineering desirable in exploring hetero-and quantumstructures for high-performance devices.…”

Section: Introductionmentioning

confidence: 99%

Dual-wavelength excited photoluminescence spectroscopy of deep-level hole traps in Ga(In)NP

Dagnelund

Huang

et al. 2015

Journal of Applied Physics

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By employing photoluminescence (PL) spectroscopy under dual-wavelength optical excitation, we uncover the presence of deep-level hole traps in Ga(In)NP alloys grown by molecular beam epitaxy (MBE). The energy level positions of the traps are determined to be at 0.56 eV and 0.78 eV above the top of the valance band. We show that photo-excitation of the holes from the traps, by a secondary light source with a photon energy below the bandgap energy, can lead to a strong enhancement (up to 25%) of the PL emissions from the alloys under a primary optical excitation above the bandgap energy. We further demonstrate that the same hole traps can be found in various MBEgrown Ga(In)NP alloys, regardless of their growth temperatures, chemical compositions, and strain. The extent of the PL enhancement induced by the hole de-trapping is shown to vary between different alloys, however, likely reflecting their different trap concentrations. The absence of theses traps in the GaNP alloy grown by vapor phase epitaxy suggests that their incorporation could be associated with a contaminant accompanied by the N plasma source employed in the MBE growth, possibly a Cu impurity. V C 2015 AIP Publishing LLC. [http://dx

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Time-resolved studies of photoluminescence in GaNxP1−x alloys: Evidence for indirect-direct band gap crossover

Cited by 87 publications

References 13 publications

Raman spectroscopy of GaP/GaNP core/shell nanowires

Raman spectroscopy of GaP/GaNP core/shell nanowires

Optimizing GaNP Coaxial Nanowires for Efficient Light Emission by Controlling Formation of Surface and Interfacial Defects

Dual-wavelength excited photoluminescence spectroscopy of deep-level hole traps in Ga(In)NP

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