Donor-Acceptor Pair Transitions in GaN

Unusual luminescence lines in GaN

“…17 and 37 may have the same origin as the Y 4 peak in our samples. The peak at about 3.37 eV observed by Kornitzer et al 13 is different from our Y 4 or Y 3 peaks because the temperature quenching of the 3.37 eV peak in Ref. 13 is much slower than that for our Y 4 or Y 3 peaks.…”

“…The 3.21 eV peak "Y 7 … The 3.21 eV peak, denoted here as Y 7 , with a few LO phonon replicas has been observed in several studies. 13,16,17,21,37 Sometimes the 3.2 eV peak appeared as a doublet with a separation of about 20-25 meV between its maxima. 13,21 This peak was attributed to an unknown acceptor 21 or to structural imperfections.…”

“…14,18,21 Others attributed the 3.42 eV peak to a transition from a donor to the valence band where the donor was assumed to be oxygen. 12,13 Some investigators suggested that the 3.42 eV peak is related to structural defects, 10,[15][16][17][18][19][20] in particular to cubic inclusions or stacking faults in the wurtzite GaN 10,18,19 or to c-axis screw dislocations. 20 The 3.42 eV peak, denoted in this study as Y 2 , appeared in many of our as-grown GaN samples with Ga and sometimes N polarity.…”

“…The origin of these peaks is controversial. For example, the commonly observed 3.42 eV peak [12][13][14][15][16][17][18][19][20][21] has been attributed to recombination between electrons bound to oxygen donors and free holes, 12,13 DAP-type transitions involving a very shallow unidentified acceptor, 14 and exciton bound to structural defects, 10,[15][16][17][18][19][20] in particular to stacking faults 17,19 and c-axis screw dislocations. 20 Even less is known about the other peaks.…”

Optical characterization of AlN/GaN heterostructures

“…The 3.40-3.45 eV PL band is one of the commonly occurring bands in Al X Ga 1ϪX N/GaN heterostructures [8][9][10][11] and GaN layers. [20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35][36][37][38] In Al X Ga 1ϪX N/GaN heterostructures this band is believed to be related to the recombination of the 2DEG with photoexcited holes. Different recombination channels have been considered as the origin of this band in GaN layers: ͑i͒ recombination of excitons bound to structural defects or to stacking faults; [20][21][22][23][24][25][26][27][28] ͑ii͒ recombination between electrons bound to a donor and free holes; [29][30][31][32][33][34][35] ͑iii͒ donor acceptor pair ͑DAP͒-type transitions involving a very shallow acceptor.…”