Low resistivity n-type ε-Ga2O3 epilayers were obtained for the first time either by adding silane to the gas phase during the metal organic vapour phase epitaxy deposition or by diffusing Sn in nominally undoped layers after the growth. The highest doping concentrations were few 1018 cm−3 and about 1017 cm−3 for Si and Sn doping, with corresponding resistivity below 1 and 10 Ω cm, respectively. Temperature dependent transport investigation in the range of 10-600 K shows a resistivity behavior consistent with the Mott law, suggesting that conduction through localized states dominates the electrical properties of Si- and Sn-doped samples. For both types of dopants, two different mechanisms of conduction through impurity band states seem to be present, each of them determining the transport behavior at the lower and higher temperatures of the measurement range.

Double crystal X‐ray diffractometry is employed to investigate residual lattice disorder in self‐ion implanted silicon after pulsed laser irradiation. The defects responsible for the observed disorder are found to decrease the lattice parameter of silicon and to extend to depths much greater than the thickness of the initial amorphized crystal. It is possible to distinguish a thin relatively undamaged surfacial layer from an underlying more disordered region. Isochronal treatments show that the crystal perfection is completely recovered at temperatures of the order of 1000 °C, whereas isothermal treatments and transmission electron microscopy observations, made on fully annealed samples, allow to evidence the presence of carbon and oxygen in the damaged crystal. The trend of the isochronal curves and the sign of the lattice strain suggest that substitutional carbon, carbon‐ and oxygen‐ related centres and multivacancy complexes are responsible for the observed residual lattice disorder.

No abstract