Highly conductive epitaxial ZnO layers deposited by atomic layer deposition

Abstract

The possibility of depositing conductive epitaxial layers with atomic layer deposition has been examined. Epitaxial ZnO layers were grown on GaN and doped with Al. The resistivity of the epitaxial layers is between 0.6 and 2*10 -4 Ωcm with both the mobilities and the carrier concentrations very high. The source of the high carrier concentration was found to be a combination of Al and Ga doping, the latter resulted by Ga atoms diffusing into the ZnO from the GaN substrate.

Influence of Carbon Modification on the Morphological, Structural, and Optical Properties of Zinc Oxide Nanoparticles Synthesized by Pneumatic Spray Pyrolysis Technique

“…The analysis has revealed that unmodified ZnO with modal nanoparticle size of 9.9 nm have an absorption edge at 374 nm and energy band gap of 3.31 eV which is larger than for bulk ZnO nanoparticle with an absorption edge at 388 nm and an energy band gap of 3.2 eV. The blue shift in the energy band gap of PSP of our synthesized samples, as compared to bulk ZnO, as previously reported, is due to the size confinement effect [31,36]. However, the absorption edges for the 0.005 M, 0.01 M, and 0.015 M C-ZnO revealed a red shift with band gap energies of 3.29 eV, 3.28 eV, and 3.26 eV, respectively.…”

“…SP methods offer the opportunity to precisely control the structural, optical, and electronic properties of nanomaterials, since the stoichiometry of the chemical precursors is governed by chemical reactions [19,20]. Moreover, aerosol processes have the potential to replace primordial costly and problematical solid state techniques for fabrication of ZnO nanostructures like the derivatives of chemical vapour deposition techniques such as plasma enhanced chemical vapour deposition (PECVD) [12][13][14][15][16][17][18] and to eliminate costly and sophisticated solid state techniques like evaporation plasma [21], anodization [22,23], spin on methods [24][25][26], sputtering [15], ion assisted deposition [27], reactive ion plating [28], laser ablation [29], filtered arc deposition [30], and atomic layer epitaxy [31]. These techniques have numerous disadvantages that limit their application on industrial scale, such as high vacuum pressure chambers requirements and high thermal processing budgets, which increase the cost of production of ZnO nanostructures and in turn increase the overall cost of production of solar cell devices with ZnO nanostructures.…”

Influence of the Lattice Mismatch on the Atomic Ordering of ZnO Grown by Atomic Layer Deposition onto Single Crystal Surfaces with Variable Mismatch (InP, GaAs, GaN, SiC)

“…On the contrary, on the GaN (0001-Ga) seeding surface, the ALD growth proceeds as a smooth pseudomorphic epitaxial process at the macroscopic scale, with coherent single-crystal stacking of ZnO onto the GaN seed and a sharp hetero-interface. This epitaxial stacking confirms and extends the results previously reported in the literature [11][12][13][14][15] on the ALD epitaxial growth of ZnO on GaN. However, it can be noted that the epitaxial relationship is obtained with a deposition at 180 • C which is lower than the temperature used in previous works [11,12].…”

A Revised Growth Model for Transparent Conducting Ga Doped ZnO Films: Improving Crystallinity by Means of Buffer Layers

“…There have been a lot of reports on the optimization of the process parameters of epitaxial and non‐epitaxial ZnO films growth by magnetron sputtering on various type of substrates . For a high quality ZnO epitaxial growth the transition layer at the “substrate‐film” interface is often not observed, while in the case of ZnO film formation on non‐oriented substrates the transition layer is always present . Many reports were directed on the investigation of the consequences of crystallinity of ZnO films and on the optimal plasma process conditions, since improving crystallinity at an early stage of film growth has a very important role for improving structural and electrical properties .…”