The influence of dislocations on optical and electrical properties of epitaxial ZnO on Si (111) using a γ-Al₂O₃buffer layer

Abstract

The structural, optical and electrical properties of the c-plane ZnO epitaxial films grown by pulsed laser deposition on a Si(111) substrate buffered with a thin layer of g-Al 2 O 3 were investigated by X-ray diffraction, transmission electron microscopy, photoluminescence (PL) and Hall measurements. Detailed structural investigation showed that the dominant structural defects in the ZnO films are threading dislocations (TDs). Experimental results manifest the edge-and screw-type of TDs influence the optical and electric properties differently; the intensity ratio between the PL yellow-green band to near band edge emission and the carrier concentration are affected mainly by the edge TD, and the FWHM of the near band edge emission is dominantly influenced by the screw TD.

The Role of Edge Dislocations on the Red Luminescence of ZnO Films Deposited by RF‐Sputtering

“…Besides, it has been evidenced from Figures 2 and 3 that the main structural defects observed in the ZnO layers correspond to TDs (screw + mixed and edge + mixed) with densities ranging from 10 8 to 10 9 cm −2 from the interface to the surface (Table 3). These values have a good agreement with previously reported results on good quality state of the art ZnO layers [3,[28][29][30]. For the analysed samples no stacking faults were identified Journal of Nanomaterials and the TD density was found to be dependent on the depth inside the film.…”

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“…5. Through TEM images, lattices of [39,40]. The Ni (III) species such as Ni 2 O 3 , seen in XPS, could hardly be identified by TEM, most likely due to its amorphous nature in our catalyst.…”

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“…4(a), of the samples grown at different temperatures were measured. The deep level emission centered around 2.2 eV, commonly known as the defect emissions attributed to the zinc interstitial or oxygen vacancies, [17][18][19] is negligible. Two dominant features are observed in the spectra: a sharp near-band edge (NBE) emission centered around 3.36 eV and a weak broadband one around 3.17 eV, noted as SX.…”