Temperature-Dependent Photoluminescence of ZnO Thin Films Grown on Off-Axis SiC Substrates by APMOCVD

Abstract

The growth of high-quality ZnO layers with optical properties congruent to those of bulk ZnO is still a great challenge. Here, for the first time, we systematically study the morphology and optical properties of ZnO layers grown on SiC substrates with off-cut angles ranging from 0° to 8° by using the atmospheric pressure meta–organic chemical vapor deposition (APMOCVD) technique. Morphology analysis revealed that the formation of the ZnO films on vicinal surfaces with small off-axis angles (1.4°–3.5°) follows the mixed growth mode: from one side, ZnO nucleation still occurs on wide (0001) terraces, but from another side, step-flow growth becomes more apparent with the off-cut angle increasing. We show for the first time that the off-cut angle of 8° provides conditions for step-flow growth of ZnO, resulting in highly improved growth morphology, respectively structural quality. Temperature-dependent photoluminescence (PL) measurements showed a strong dependence of the excitonic emission on the off-cut angle. The dependences of peak parameters for bound exciton and free exciton emissions on temperature were analyzed. The present results provide a correlation between the structural and optical properties of ZnO on vicinal surfaces and can be utilized for controllable ZnO heteroepitaxy on SiC toward device-quality ZnO epitaxial layers with potential applications in nano-optoelectronics.

Nanostructured ZnO‐CQD Hybrid Heterostructure Nanocomposites: Synergistic Engineering for Sustainable Design, Functional Properties, and High‐Performance Applications

“…Emissions in the green and yellow regions of the light spectrum arise from defects within the ZnO crystal lattice and offer information about these defects [113] . Temperature‐dependent PL studies further elucidate ZnO′s photoluminescence behaviour by shedding light on excitonic states [114] . Beyond thin films, ZnO′s photoluminescence properties find applications in UV‐emitting devices, lasers, sensors, and various optoelectronic devices [115] .…”

“…[113] Temperature-dependent PL studies further elucidate ZnO's photoluminescence behaviour by shedding light on excitonic states. [114] Beyond thin films, ZnO's photoluminescence properties find applications in UV-emitting devices, lasers, sensors, and various optoelectronic devices. [115] Combining ZnO with carbon quantum dots (CQDs) offers significant promise for enhanced photocatalytic performance.…”

Influence of ZnO Nanostructure Morphologies on Perovskite Solar Cell Performance: A Review

“…In ZnO-based devices, the vicinal surface and interfacial behaviors of heterogeneous layers are important. Recently, Shtepliuk et al [83] showed a correlation between the structural and optical properties for such surfaces and interfaces in ZnO, using epitaxial films grown on SiC for nano-optoelectronic applications. Figure 15 is an overview of the main issues of device stability.…”

Behavior of Al Impurity in ZnO Films: Influence of Al‐Level Doping on Structure, X‐Ray Photoelectron Spectroscopy and Transport Properties

“…In several of our previous articles, we have comprehensively investigated the effect of deposition technological parameters on the structural, optical, and electrical properties of zinc oxide films. [2][3][4][5] However, the problem of small electroactivity (EA) for introduced donor impurities into the ZnO lattice still exists. [6] EA of the impurity is a very important characteristic of a doped semiconductor.…”