Photoluminescence of highly excited AlN: Biexcitons and exciton-exciton scattering

Abstract

Low-temperature photoluminescence spectra of nominally undoped high quality AlN layers on SiC and Al2O3 substrates are reported. Under high excitation conditions, we observe several bands that increase superlinearly with the excitation density. Based on temperature and excitation level dependences recorded on different samples, we identify a band 36 meV below the free A-exciton transition as due to exciton-exciton scattering (P2 band) and a second band down-shifted from the A-exciton transition by 27 meV as due to biexciton recombination. The combined data yield an exciton binding energy of 48 meV.

Anisotropic absorption and emission of bulk(11¯00)AlN

“…These values result from the low-temperature results of this study; an overview of previously published values is summarized in Table III. Electron-hole interaction leads to the formation of excitons with the binding energy of 55 meV or slightly smaller 55,56 for the A exciton, while the binding energies for B and C excitons were found to be similar. 16 We performed SE experiments at different temperatures between T = 10 and 295 K. The dependence of the anisotropic ε 2 spectra around the band gap is presented in Fig.…”

Deep ultraviolet emission mechanisms in highly excited Al0.79Ga0.21N/AlN quantum wells

“…Highly excited emission mechanisms have been studied for various semiconductors such as GaN [5][6][7][8], AlN [9], and ZnO [10]. For GaN, the Mott transition from the exciton many body effect to electron-hole plasma (EHP) was observed as the excitation intensity was increased [5].…”

“…For AlN, PL under high excitation conditions below the Mott density was reported. P line related to exciton-exciton scattering was observed clearly [9]. In this paper, we assess power dependence of PL in Photon Energy (eV) PL Intensity (arb.…”

Excitons in Solids from Time-Dependent Density-Functional Theory: Assessing the Tamm-Dancoff Approximation

“…Experimental exciton binding energies (in meV) are taken from Refs. [26][27][28][29][30][31][32][33] and shown only for comparison. We find that the TDA consistently underestimates the exciton binding energies compared to the full calculation.…”