Si and Sn doping of epsilon-Ga2O3 layers

Low resistivity n-type epsilon-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 undopeci, layers after the growth. The highest doping concentrations were few 10(18) cm(-3) and about 10(17) cm(-3) for Si and Sn doping, with corresponding resistivity below 1 and 10 Omega 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 preserit, each of them determining the transport behavior at the lower and higher temperatures of the measurement range.