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(a) XRD out-of-plane symmetric 2Θ-ω scan of SnO(001) layer on YSZ(100) grown at different substrate temperatures. The film grown at 50 °C was amorphous, between 150 and 450 °C, phase-pure single-crystalline SnO(001) layers are obtained. At a substrate temperature of 550 °C, secondary Sn 3 O 4 phases are observed and growth at 650 °C showed a mixed phase with negligible SnO(001) contribution. (b) FWHM of the SnO 002 omega rocking curve as a function of the substrate temperature.
Source publication
By employing a mixed SnO2 + Sn source, we demonstrate suboxide molecular beam epitaxy (S-MBE) growth of phase-pure single-crystalline metastable SnO (001) thin films on Y-stabilized ZrO2 (001) substrates at a growth rate of ∼1.0 nm/min without the need for additional oxygen. These films grow epitaxially across a wide substrate temperature range fro...
Contexts in source publication
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... symmetric 2Θ-ω XRD scans were used to investigate the out-of-plane orientation of the layers. Figure 5(a) shows representative results for layers grown at different YSZ (001) substrate temperatures, wide-angle scans of selected samples between 10 and 120° are shown in Fig. S2(a) in the supplementary material, and similar wide-angle scans for a sample grown on r-plane Al 2 O 3 are shown in Fig. S2(b) in the supplementary material. Typical streaky RHEED patterns observed during the growth of SnO (001) layers are also shown in Fig. S3 in the supplementary material. ...
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... in previous S-MBE SnO growth on r-plane Al 2 The in-plane epitaxial relationship between the SnO (001) layer and the substrate was investigated for the phase-pure SnO (001) thin films by skew-symmetric Φ-scans of the SnO 112 and YSZ 111 reflections with rotational angle Φ around the surface normal (see Fig. S4 in the supplementary material). From Fig. 5(a), we confirm the epitaxial relationship SnO(001)||YSZ(001) and SnO (110)||YSZ (010) for the out-of-plane and in-plane directions, respectively, indicating a 45° in-plane rotation of the SnO crystal lattice with respect to the YSZ one. This is in agreement with our previously grown PA-MBE thin films, where the same epitaxial relations ...
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... The texture map confirms the presence of a predominantly single domain as observed in the Φ-scans. The scan shows four distinct peaks at a tilt angle of Ψ = 51.63° corresponding to the tilt of the (101) plane with respect to the (001) planes. Other Streaky peaks not labeled observed in the texture map are due to the substrate holder as shown in Fig. S5 in the supplementary material. Texture maps also show that distinct in-plane epitaxial relationships are possible for these samples on YSZ(001) substrates unlike randomly oriented samples observed for growths on Ga 2 O 3 substrates. 17,18 To clarify the phase composition of the grown epilayers beyond the limited capabilities of our ...
Citations
Polycrystalline α-Ga2O3 thin films containing secondary phase SnO were grown on BaF2 substrates by magnetron sputtering. The impurity tin concentration, electron concentration, and room temperature mobility of the α-Ga2O3 films are 4.5 × 10²⁰ cm⁻³, 1.5 × 10¹⁵ cm⁻³, and 26.9 cm² V⁻¹ s⁻¹, respectively, determined by secondary ion mass spectrometry and Hall effect experiments. The mobility vs temperature dependence confirms that the electrons are mainly subject to polar optical phonon scattering and ionized impurity scattering in the temperature range of 160–400 K. Two ionization energies, 29 and 71 meV, were determined for different temperature ranges by logarithmic resistivity vs the reciprocal of temperature, where the former is the shallow donor SnGa formed by the incorporation of tin into gallium sites. The latter is the shallow acceptor VSn–H associated with secondary phase SnO, and it is the electrical compensation of this shallow acceptor that results in the very low carrier concentration of α-Ga2O3 films. The photoluminescence spectrum exhibits 280 and 320 nm UV radiation, where 280 nm is due to the radiation recombination of electrons trapped by the deep donor state (EC−1.1 eV) with holes trapped by the VSn–H complex. In addition, there are several narrow radiation peaks in the visible region, and the energy levels involved in the radiation transitions are determined one by one after excluding the effects of interference and diffraction.
(La and Ga)-doped tin monoxide [stannous oxide, tin (II) oxide, SnO] thin films were grown by plasma-assisted and suboxide molecular beam epitaxy with dopant concentrations ranging from ~5×10^18 to 2×10^21 cm^-3. In this concentration range, the incorporation of Ga into SnO was limited by the formation of secondary phases observed at 1.2×10^21cm^3 Ga, while the incorporation of La showed a lower solubility limit. Transport measurements on the doped samples reveal that Ga acts as an acceptor and La as a compensating donor. While Ga doping led to an increase in the hole concentration from 1×10^18--1×10^19cm^-3 for unintentionally doped (UID) SnO up to 5×10^19cm^-3, La-concentrations well in excess of the UID acceptor concentration resulted in semi-insulating films without detectable n-type conductivity. Ab initio calculations qualitatively agree with our dopant assignment of Ga and La and further predict In_Sn to act as an acceptor as well as Al_Sn and B_Sn as donors. These results show the possibilities of controlling the hole concentration in p-type SnO, which can be useful for a range of optoelectronic and gas-sensing applications.
