Synthesis and optical properties of single crystal ZnO nanorods

Abstract

ZnO nanorods were epitaxially grown by metalorganic chemical vapour deposition (MOCVD) on sapphire (0001) and substrates. The nanorods were elongated along the ZnO c-axis which was parallel to the substrate normal. Good alignment among the rods was achieved both in the length direction and in the in-plane orientations. The line width of bound exciton emissions was meV at low temperatures. Emissions due to free excitons were observed from low to room temperature. Biexciton emissions were observed up to K. The band edge emission at room temperature was found to be a mixture of emissions due to free excitons and other impurity-related emissions, indicating that care must be taken when assigning the emission peak at higher temperatures.

Indirect optical transition due to surface band bending in ZnO nanotubes

“…30͒ to 383 nm, 31 and the exact energy position depends on the contribution between the FX, FX-phonon replica and the transition between free electrons to acceptor bound holes. [32][33][34][35] The DLE band had recently been identified and at least two defect origins ͑V O and V Zn ͒ with different optical characteristics were claimed to contribute to this DLE band. [36][37][38] As seen from Fig.…”

Annealing effects on optical properties of low temperature grown ZnO nanorod arrays

“…29͒ to 383 nm, 30 and the exact energy position depends on the contribution between the free exciton and the transition between free electrons to acceptor bound holes. [31][32][33][34] The deep level emission band has previously been attributed to several defects in the crystal structure such as 42 and extrinsic impurities such as substitutional Cu. 43 Recently, this deep level emission band had been identified and at least two different defect origins ͑V O and V Zn ͒ with different optical characteristics were claimed to contribute to this deep level emission band.…”

Surfactant free hydrothermally derived ZnO nanowires, nanorods, microrods and their characterization

“…These oxides have two unique structural features: mixed cation valencies and an adjustable oxygen deficiency, which are the bases for creating and tuning many novel materials properties [5]. ZnO is a well-known n-type wide band gap semiconductor (E g =3.37 eV) with a large exciton binding energy of 60 meV [6]. As a result the material is transparent to visible light but not to UV light.…”