Effect of Ti Doping on the Crystallography, Phase, Surface/interface Structure and Optical Band Gap of Ga2O3 Thin Films

Journal Article · Sun Sep 01 00:00:00 EDT 2019 · Journal of Materials Science

DOI:https://doi.org/10.1007/s10853-019-03663-w· OSTI ID:1566763

Manandhar, Sandeep ^[1]; Battu, Anil K. ^[1]; Tan, Susheng ^[2]; Panat, Rahul ^[3]; Shutthanandan, Vaithiyalingam  ^[4]; Ramana, C.V. ^[1]

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1. University of Texas at El Paso
2. University of Pittsburgh
3. Carnegie Mellon University
4. BATTELLE (PACIFIC NW LAB)

The effect of titanium (Ti) doping on the crystal structure, phase, surface/interface chemistry, microstructure and optical band gap of gallium oxide (Ga2O3) (GTO) films is reported. The Ti content was varied from 0 to * 5 at% in cosputtering, using Ga2O3 ceramic and Ti metal targets, deposited GTO films produced. The sputtering power to the Ti target was varied in the range of 0–100 W, while keeping the sputtering power to Ga2O3 constant at 100 W, to produce GTO films with 0–5 at% Ti. The Ti-incorporation-induced effects were significant for the crystal structure, phase, surface/interface chemistry and morphology, which in turn induce changes in the band gap. The high-resolution core-level X-ray photoelectron spectroscopy (XPS) analyses confirm that the Ga ions exist as Ga3? in both intrinsic Ga oxide and GTO films. However, XPS data reveal the formation of Ga2O3–TiO2 films with the presence of Ti4? ions with increasing Ti sputtering power, i.e., higher Ti contents in GTO. Evidence for the formation of nanocrystalline Ga2O3–TiO2 films was also found in the structural analyses performed using electron microscopy and grazing incidence X-ray diffraction. Significant band gap reduction (Eg * 0.9 eV) occurs in GTO films with increasing Ti dopant concentration from 0 to 5 at%. A correlation between the Ti dopant concentration, surface/interface chemistry, microstructure and band gap of GTO films is established.

• Research Organization: Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-76RL01830
• OSTI ID: 1566763
• Report Number(s): PNNL-SA-147395
• Journal Information: Journal of Materials Science, Vol. 54, Issue 17
• Country of Publication: United States
• Language: English