The effect of Gd doping on the atomic and electronic structure of HfO$_{2}$ thin films.

HfO$_{2}$ is a promising oxide for many applications, including high-$k$ gate dielectric for CMOS devices. In addition, Gd-doped HfO$_{2}$ could lead to a dilute magnetic semiconductor and provide an efficient neutron detection medium due to huge neutron absorption cross section of Gd. Gd-doped HfO$_{2 }$films deposited on both $p-$type and $n$-type silicon by PLD retain monoclinic phase at small doping levels, but can be stabilized in fluorite phase by increased doping [1]. At small doping levels, photoemission measurements indicate $n$-type character of the films as a result of overcompensation with oxygen vacancies. Depending on a doping level, the films form heterojunctions with good rectifying properties on $n$- or $p$-type silicon. Preliminary results show the potential ability of the formed diode structures to detect neutrons. [1] Ya.B.Losovyj, I.Ketsman et al.,APL, 91, 132908, (2007)