Preparation and optical properties of ZnO/Zn0.9Mg0.1O multiple quantum well structures with various well widths grown on c-plane sapphire

Exciton Localization of High-Quality ZnO/MgxZn1–xO Multiple Quantum Wells on Si (111) with a Y2O3 Buffer Layer

“…As compared to MQWs with L w = 1.6 and 2.7 nm, not only the larger change in S-shaped dependence but also the larger full width at half-maximum value were apparently observed in the MQWs with L w = 5.6 nm. These are ascribed to the triangle-sharp potential well from QCSE induced by the existence of larger internal electric field , and influences of alloy fluctuation. Moreover, for 10 K < T < 50 K, because of the relatively longer relaxation time of the exciton with increasing temperature, excitons have more opportunity to relax into the lower energy tail states caused by the inhomogeneous potential fluctuations ( E potential = 4–5 meV) before radiative recombination.…”

“…34 The integrated intensity of the NBE emission of ZnO/ ZnMgO MQWs with L w = 1.6, 2.7, and 5.6 nm as a function of inverse temperature are given in Figure S5a. The temperaturedependent integrated PL intensity can be described as the Arrhenius expression: 33,35,36…”

“…The integrated intensity of the NBE emission of ZnO/ZnMgO MQWs with L w = 1.6, 2.7, and 5.6 nm as a function of inverse temperature are given in Figure S5a. The temperature-dependent integrated PL intensity can be described as the Arrhenius expression: ,, where I 0 is the integrated intensity at 0 K, k b is Boltzmann’s constant, E b1 and E b2 are the active energies, and A and B are the corresponding constants. We found E b1 was about 5 meV and might correspond to the energy of exciton bound to a neutral donor or localization potential due to alloy fluctuation or well width variation; E b2 responsible for the high-temperature part of I ( T ) are 41, 60, and 73 meV for L w = 5.6, 2.7, and 1.6 nm samples, respectively, which correspond to the exciton binding energy in the quantum wells.…”

UV electroluminescence emissions from high-quality ZnO/ZnMgO multiple quantum well active layer light-emitting diodes

“…It indicates that emissions of MQWs are attributed to the recombination of the localized exciton in the ZnO well and blue-shift is due to the quantum confinement effect (QCE). 14,25 The recombination of the localized exciton in the ZnO well layer and undetected emission from the Zn 0.9 Mg 0.1 O barrier layer both certificate the efficient carrier injection from barrier to well. UV emissions varied monotonically from 373 nm to 366 nm as the MQWs well width reduced from 8 nm to 2 nm, as shown in Fig.…”

Improved photoluminescence performance of MgZnO films by alloying beryllium

“…heterojunction band alignment with tunable band offsets depending on Mg composition [7]. ZnO/MgZnO quantum wells luminescence shows quantization behavior and an enhancement of the exciton binding energy up to 96 meV [8][9][10]. The two-dimensional electron gas (2DEG) confined at the Mg x Zn 1−x O/ZnO heterointerface shows an improved electron mobility of 130,000 cm 2 V −1 s −1 [11].…”