Photoluminescence of MBE grown wurtzite Be-doped GaN

Abstract

We report new lines in the photoluminescence (PL) spectrum of lightly Be-doped GaN. The low-temperature PL spectrum of the lightly doped sample is dominated by a transition at 3.385 eV with first and second LO phonon replicas. Power-resolved PL measurements showed that the peak at 3.385 eV narrowed in width and shifted to higher energies with increasing excitation intensity. Thus the transition is attributed to donor-to-acceptor recombination, involving a Be acceptor of optical ionization energy of between 90 and 100 meV. This is much shallower than the acceptor level of 250 meV induced by Mg doping. Increasing the doping, however, resulted in a quenching of the band-edge luminescence and the appearance of a broad transition centred around 2.4 eV which we assign to a complex involving Be. Undulations on the peak were consistent with interference effects. On increasing the doping level even further all luminescence was quenched.

Characterization of Be-Implanted GaN Annealed at High Temperatures

“…For this case, the ionization energy of Be acceptors was calculated to be 150 ± 10 meV [12]. Dewsnip and co-workers [13] also observed a new line in GaN samples doped with Be during growth at 3.376 eV. However, they calculated the ionization energy to be 90-100 meV due to the assumption that this line is a donor-to-acceptor transition.…”

“…The low temperature PL spectra of a Be-implanted GaN sample with a dose of 5x10 13 cm -2 are summarized in Fig. 3.…”

“…This incorporation reduces the hole mobility due to the enhanced carrierimpurity scattering processes [11]. Beryllium (Be) is a more promising candidate for p-type doping given its measured lower ionization energy of ~ 0.15 eV [12,13].…”

First-principles studies of beryllium doping of GaN

“…[7][8][9][10][11][12][13][14][15] These experimental studies have involved both wurtzite and cubic phases of GaN; the cubic phase can be obtained by growth on cubic substrates, under appropriately tailored conditions. Another technique for Be incorporation that has been attempted is ion implantation.…”

High Responsivity in GaN Ultraviolet Photodetector Grown on a Periodic Trapezoid-Column Patterned Sapphire Substrate

“…It can be seen clearly that the PL spectrum of the GaN film grown on the CFSS exhibits a relatively weak band-edge emission at 3.468 eV and a notorious yellow band (YB) emission near 2.3 eV. (32) In contrast, a strong band-edge-emission PL peak with a sharp 14 meV FWHM is observed from the GaN film grown on the PTCPSS. The increase in the PL intensity and the absence of YB emission indicate that the crystal quality is improved and the TD density is reduced for the GaN film grown on the PTCPSS.…”