Decrease in the binding energy of donors in heavily doped GaN:Si layers

We report the results of time-resolved and temperature-dependent stationary photoluminescence investigations of the defects responsible for emission in the visible spectral range in heavily silicon-doped AlxGa1–xN layers grown by molecular beam epitaxy on sapphire substrates. The emission band was attributed to donor–acceptor transitions. The transitions were described using the one-dimensional configuration coordinate model taking into account the high-doping regime. An increase in Al content from 0.56 to 1 leads to an increase in the acceptor ionization energy from 1.4 to 1.87 eV. The value of the Franck–Condon shift is about 1 eV at x = 0.56–0.74 and decreases to 0.8 eV at x > 0.74. The changes in the donor–acceptor transition energy parameters with increasing silicon concentration are discussed.

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“…where a B is the Bohr radius of the donor state. Within the framework of the hydrogen atom model a B can be estimated as 37) a a m m 11…”

Section: Discussionmentioning

confidence: 99%

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped Al_xGa_1−xN:Si layers with Al contentx> 0.5

Osinnykh

Малин

Milakhin

et al. 2019

Jpn. J. Appl. Phys.

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“…The luminescence at 𝑌 4 " and 𝑌 7 are associated with the excitons bound to surface structural defect and structural defects in the bulk material, respectively. At higher doping densities beyond 10 19 cm -3 , the spacing between the electrons becomes smaller than the exciton Bohr radius, causing the screening of electron-hole Coulomb interaction [32], leading to lower probability of the formation of excitons. Moreover, 𝑌 4 " and 𝑌 7 peaks are characterized with small FWHM [31], similar to the additional peak samples 3 and 4 of our study, as shown in Fig.…”

Section: *Obtained From Raman Measurementsmentioning

confidence: 99%

Effects of Si doping well beyond the Mott transition limit in GaN epilayers grown by plasma-assisted molecular beam epitaxy

Lingaparthi¹,

Dharmarasu²,

Radhakrishnan³

et al. 2021

J. Phys. D: Appl. Phys.

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The effects of Si doping well beyond the Mott transition limit on the structural, electrical, and optical properties of plasma assisted molecular beam epitaxy grown GaN layers were studied. Si doping up to a doping density of <1.0 × 1020 cm−3 resulted in smooth surface morphologies and almost strain free 500 nm thick GaN layers on 50 mm Si (111) substrate. In this doping range, the crystal quality improved with increased Si doping. However, GaN layers with doping density of >1.0 × 1020 cm−3 resulted in rough surface morphology and degraded crystal quality. It also showed higher tensile strain, but did not result in cracking. Irrespective of the surface morphology and structural quality, the sheet resistance systematically decreased with increased carrier concentration up to and beyond the doping density of 1.0 × 1020 cm−3. PL study revealed three distinctive characteristics with Si doping: first, yellow luminescence is absent in Si doped samples— an indication of occupied VGa-ON and CN states in the bandgap; second, a distinctive luminescence peak is observed next to the band edge luminescence (BEL) for the samples doped beyond 2.1 × 1019 cm−3—probably an indication of localization of some of the electrons either at donors or at excitons bound to defects; third, blue shift of the BEL is not matching with the calculated Moss–Burstein shift for doping densities beyond 2.1 × 1019 cm−3—an indication of some of the electrons not occupying higher levels of conduction band, which is consistent with the second observation of localization of electrons near the donors or excitons bound to surface defects.

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“…In QWs, there is no theory that predicts a value for the binding energy at any doping concentration. Nonetheless, in bulk systems it has been generally shown, theoretically and experimentally, that the binding energy decreases when the doping concentration increases [13,[35][36][37].…”

Section: A Insulating Regimementioning

confidence: 99%

Temperature dependence of the spin relaxation time of donor-bound electrons immersed in a CdTe quantum well

et al. 2019

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Decrease in the binding energy of donors in heavily doped GaN:Si layers

Cited by 9 publications

References 40 publications

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped Al_xGa_1−xN:Si layers with Al contentx> 0.5

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped Al_xGa_1−xN:Si layers with Al contentx> 0.5

Effects of Si doping well beyond the Mott transition limit in GaN epilayers grown by plasma-assisted molecular beam epitaxy

Temperature dependence of the spin relaxation time of donor-bound electrons immersed in a CdTe quantum well

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Decrease in the binding energy of donors in heavily doped GaN:Si layers

Cited by 9 publications

References 40 publications

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped AlxGa1−xN:Si layers with Al contentx> 0.5

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped AlxGa1−xN:Si layers with Al contentx> 0.5

Effects of Si doping well beyond the Mott transition limit in GaN epilayers grown by plasma-assisted molecular beam epitaxy

Temperature dependence of the spin relaxation time of donor-bound electrons immersed in a CdTe quantum well

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Product

Resources

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Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped Al_xGa_1−xN:Si layers with Al contentx> 0.5

Donor–acceptor pair emission via defects with strong electron–phonon coupling in heavily doped Al_xGa_1−xN:Si layers with Al contentx> 0.5