Preparation of Ge/ZnO nanocomposites by radio frequency alternate sputtering

Effects of rapid thermal annealing on the structural and local atomic properties of ZnO: Ge nanocomposite thin films

“…Early studies on Ge nanocrystals (Ge-ncs) embedded host oxide thin films demonstrate significant change on the optical properties and observed changes are usually attributed to quantum confinement of electron hole pairs in Ge-ncs. [13][14][15][16] It is imperative to understand the structural nature of Ge-ncs as well as the nature of the interface between the Ge-ncs and oxide matrix so as to interpret the optical properties. The thrust of current literature is centered on Ge-ncs embedded in SiO 2 due to the ease of compatibility in standard Si based semiconductor processing.…”

“…In the literature, there is limited number of studies on Ge nanoparticles embedded ZnO thin film structures. 13,[17][18][19] In almost all of the referenced works, similar route of synthesis has been followed, that is, sequential sputtering of Ge and ZnO layers followed by a conventional furnace annealing. However, in this work, we have explicitly utilized rapid thermal annealing (RTA), as it is known to be an effective thermal process for the crystallization Ge nanoparticles.…”

Rapid thermal annealing induced formation of Ge nanoparticles in ZnO thin films: A detailed SAXS study

“…The fact that the energy difference between indirect and direct band transitions for Ge of about 0.12 eV makes it even more attractive for the purpose of changing the electronic structure around the band edge. Earlier studies on Ge nanoparticles (Ge-np) embedded host oxide thin films demonstrate significant change on the optical properties and observed changes are usually attributed to quantum confinement of electron-hole pairs in Ge-np [8][9][10]. Current literature is mostly focused on Ge-np embedded in SiO 2 due to the ease of compatibility in standard Si based semiconductor processing.…”

Formation of ST12 phase Ge nanoparticles in ZnO thin films

“…Current literature mostly utilizes SiO 2 as the embedding medium due to already developed Si based processing technology [16][17][18][19]. However, ZnO is also suggested to be a potential candidate especially for photovoltaic applications [20,21]. ZnO has advantageous features such as larger exciton binding energy ( $ 60 meV) as compare to other wide band gap materials (such as GaN and ZnSe) and high resistance to photo corrosion.…”

“…Moreover, electron affinities of Ge and ZnO being close to each other is expected to lead less confining potential for the light generated charge carriers [22,23]. In the literature, although there have been several works on Ge doped ZnO thin film structures [24][25][26] the number of works on Ge nanoparticles embedded in ZnO matrix is limited [20,21,27]. In these studies, ZnO: Ge nanocomposite structures have been commonly formed by conventional furnace annealing of sputter deposited as-prepared multilayered samples so as to promote formation of Ge nanoparticles in ZnO host.…”