Band-gap renormalization and band filling in Si-doped GaN films studied by photoluminescence spectroscopy

Abstract

We have studied band-gap renormalization and band filling in Si-doped GaN films with free-electron concentrations up to 1.7 x 10(exp19) cm(-3) , using temperature-dependent photoluminescence (PL) spectroscopy. The low-temperature (2 K) PL spectra showed a line-shape characteristic for momentum nonconserving band-to-band recombination. The energy downshift of the low-energy edge of the PL line with increasing electron concentration n, which is attributed to band-gap renormalization (BGR) effects, could be fitted by a n(1/3) power law with a BGR coefficient of - 4.7 X 10(exp-8) eV cm. The peak energy of the room-temperature band-to-band photoluminescence spectrum was found to decrease as the carrier concentration increases up to about 7 X 10(exp18) cm(-3) followed by a high-energy shift upon further increasing carrier concentration, due to the interplay between the BGR effects and band filling. The room-temperature PL linewidth showed a monotonic increase with carrier concentration, whic h could be described by a n(2/3) power-law dependence

Electrical properties and optical bandgaps of AlInN films by reactive sputtering

“…8 carriers, structural defects, residual stresses and inhomogeneous microstructures [24][25][26]. The bandgap data of Al-rich AlInN films obtained by Yamaguchi et al employing photoluminescence (PL) are lower than those determined in this investigation.…”

Effect of silicon and oxygen doping on donor bound excitons in bulk GaN

“…The model is in a good qualitative agreement with experimental data and supports the large effect of BGN in GaN even at moderate doping concentrations. The shift of the PL peak to lower energies becomes even more pronounced in highly doped GaN layers; 20 however, for carrier concentrations above the Mott density, the Burstein-Moss shift of the absorption edge to the higher energies has to be taken into account. 21,22 Since we study here relaxed bulk HVPE GaN we can likely neglect the strain effect on the PL peak position observed in both undoped and Si-doped samples.…”

Reduction of leakage current by O2 plasma treatment for device isolation of AlGaN/GaN heterojunction field-effect transistors

“…The shallow donor of the etched u-GaN may be the etching damage of the nitrogen vacancy V N according to our previous work [9,10], whereas the deep acceptor may be the native defect of the gallium vacancy V Ga [11][12][13]. The near band-edge luminescence intensity of all the samples was weaker than the YL intensity, which could be primarily attributed to the non-radiative centers at low doping concentrations in the u-GaN layer [14][15][16]. The ripples visible in the YL band from samples without treatment (Fig.…”