Donor bound excitons involving a hole from the B valence band in ZnO: Time resolved and magneto-photoluminescence studies

Abstract

Time-resolved and magneto-photoluminescence (PL) studies are performed for the so-called I(6)(B) and I(7)(B) excitonic transitions, previously attributed to neutral donor bound excitons involving a hole from the B valence band (VB), D(0)X(B). It is shown that PL decays of these emissions at 2 K are faster than that of their I(6) and I(7) counterparts involving an A VB hole, which is interpreted as being due to energy relaxation of the hole assisted by acoustic phonons. From the magneto-PL measurements, values of effective Lande g factors for conduction electrons and B VB holes are determined as g(e) = 1.91, g(h)(parallel to) = 1.79, and g(h)(perpendicular to) = 0, respectively.<p>|</p

Efficient Auger Charge-Transfer Processes in ZnO

“…The hole g tensor, on the other hand, has an axial symmetry along the crystallographic c axis with the principle hole g values of g k h ¼ −1.44 AE 0.04 and jg ⊥ h j ¼ 0.74 AE 0.04. We note that the deduced hole g factors are significantly different from the values reported for bound exciton transitions in ZnO that involve effective mass holes from the A-or B-valence bands [30,31,[33][34][35]. For all of the above mentioned excitons, g ⊥ h is close to zero, in agreement with the g ⊥ h values of the A-and B-valence bands of ZnO [30], while in our case g ⊥ h is significantly higher (approximately 0.7).…”

Photoluminescence investigations of ZnO micro/nanostructures

“…According to the selection rules, Γ 7 → Γ 9 transitions are allowed when light is oriented in a way that 𝐸 ⃗ ⊥ 𝑐 , while the Γ 7 → Γ 7 transitions are permitted for both polarizations (perpendicular and parallel) [30]. The energy separation of the A and B electronic states has been reported as 4.9 meV [27,31], whereas 43.7 meV corresponds to the energy difference between B and C [1]. [1,27]).…”

Magneto-optical properties and recombination dynamics of isoelectronic bound excitons in ZnO

“…of the order of 0.7-1.1 ns that is determined by their recombination lifetimes [7]. On the other hand, PL transients of excitonic transitions that originate from exciton excited states are much faster due to fast energy relaxation from the excited to the ground state [6]. This fast transient component is obvious, e.g.…”

“…A . Lying about 4.4 meV above these lines are the weaker and spectrally broader peaks related to the D 0 X transitions involving a B-VB hole [5,6], D 0 X B -see e.g. the I 6 B line in Fig.…”