Resonant Raman scattering and photoluminescent properties of nonpolara-plane ZnO thin film on LiGaO₂substrate

Abstract

Nonpolar a-plane ZnO thin films are grown on LiGaO2 substrates and their optical and vibronic characteristics are investigated. Raman spectroscopy under nonresonant and resonant excitations shows the phase purity and resonant multiphonon process. From multiphonon Raman peaks up to the 6th order in the resonant spectra, the LO phonon frequencies for wave vectors away from the Γ point are estimated using the cascade model. Polar LO phonons with E1 symmetry play an important role in the indirect transitions of hot excitons. The optical anisotropy has been studied on the basis of polarization-dependent photoluminescence. The origin of photoluminescence is studied and a donor binding energy of 74.6 meV is found.

Enhanced Photocatalytic Performance of ZnO Nanorods Coupled by Two‐Dimensional α‐MoO3 Nanoflakes under UV and Visible Light Irradiation

“…The Raman spectra of both MoO 3 /ZnO and MoO 3− x /ZnO samples are presented in Figure a. For comparison, the Raman spectrum of the ZnO NR substrate is also shown here, where the dominant peak at =429 cm −1 is attributed to the E 2 H mode of the wurtzite ZnO structure . The Raman peaks centered at =331, 360, 429, 860, and 950 cm −1 were observed for both nanohybrids.…”

“…The room‐temperature PL spectra in the near‐band‐edge (NBE) range of our photocatalysts are shown in Figure . As expected, the NBE band centered at 3.28 eV of the pristine ZnO NRs mainly originated from the free exciton recombinations from the ZnO NRs . For both composite samples, the PL bands are similar to that of the pristine ZnO NRs, however, the PL intensities are apparently reduced.…”

Facile and Cost‐Efficient Synthesis of Quasi‐0D/2D ZnO/MoS2 Nanocomposites for Highly Enhanced Visible‐Light‐Driven Photocatalytic Degradation of Organic Pollutants and Antibiotics

“…The photoluminescence spectra (PL) were obtained by using a He–Cd laser (Kimmon, IK series) with an excitation wavelength 325 nm at room temperature. The Raman scattering measurements were performed in a backscattering configuration on a micro‐Raman setup equipped with Jobin–Yvon spectrometer . Raman spectra were measured by using a red light laser (633 nm).…”

“…The Raman scattering measurements were performed in ab ackscattering configuration on am icro-Raman setup equipped with Jobin-Yvon spectrometer. [36] Raman spectra were measured by using ar ed light laser (633 nm).…”

“…These excellent chemical and physical properties turn ZnO into am ultifunctional materialf or numerousa pplications in electronics, optoelectronics, catalysis and sensors. [35][36][37] ZnO nanomaterial itself has potential in photocatalysis due to its photosensitivity,l ow cost, nontoxicity,a nd excellent stability. Compared with TiO 2 ,Z nO is more cost-effective and hash igher charge carrier mobility andl onger carrier lifetime.…”