Characterization of the green band in photoluminescence spectra of heavily doped Al_xGa_{1− x}N:Si with the Al content x > 0.5

Abstract

We report time-resolved and temperature-dependent photoluminescence investigations of green photoluminescence in heavily doped Al x Ga1− x N:Si films grown by molecular beam epitaxy on sapphire substrates. The green band dominates in the photoluminescence spectra of Al x Ga1− x N:Si films with the Al content higher than 0.5. This band is attributed to donor–acceptor and free electron–acceptor transitions involving the same acceptor. Donor and acceptor binding energies of about 50 and 930 meV, respectively, were obtained. The donor was assigned to the Si atom on the Ga/Al site; the acceptor might be the C atom on the N site or a complex comprising a Ga/Al vacancy and a shallow donor.

Optical signatures of silicon and oxygen related DX centers in AlN

“…Its central position also shows a minor upshift by some 50 meV over this T range, although the bandgap decreases by ≈50 meV, that is there must occur some kind of thermal excitation into close lying excited initial states of the transition. Osinnykh et al reported PL spectra even up T = 1000 K, which show a further upshift by ≈100 meV as compared to the T = RT position.…”

Model for the deep defect‐related emission bands between 1.4 and 2.4 eV in AlN

“…Based on transmission measurements, the acceptor involved was assigned to carbon on nitrogen site () or carbon‐related complexes. Osinnykh et al studied this PL band in N and found it to shift only slightly with composition variation in the range . They also suggest () or a vacancy complex as the strongest candidates for the acceptor.…”

Изменение характера биаксиальных напряжений при возрастании x от 0 до 0.7 в слоях Al-=SUB=-x-=/SUB=-Ga-=SUB=-1-x-=/SUB=-N:Si, полученных методом аммиачной молекулярно-лучевой эпитаксии

“…Интенсивное " зеленое" излучение появлялось в слоях с содержанием алюминия x = 0.6−0.7 при кон-центрации атомов кремния порядка 5 · 10 19 см −3 . В ра-боте [2] было показано, что излучение имеет донорно-акцепторный и зона-акцепторный механизмы рекомбина-ции, где донором является кремний на месте катиона, ак-цептором предположительно является трехкратно заря-женная катионная вакансия. Концентрация атомов крем-ния может быть управляемо повышена до 10 20 см −3 [3], что влияет на величину упругих напряжений и концен-трацию дефектов кристаллической решетки.…”