Neutron Detection Utilizing Gadolinium Doped Hafnium Oxide Films; Master's thesis

摘要

Gadolinium (Gd) doped hafnium oxide (HfO2) was deposited onto a silicon substrate using pulsed laser deposition. Synchrotron radiation was used to perform Gd L3-edge extended X-ray absorption fine structure (EXAFS) measurements on 3%, 10%, and 15% doped HfO2 samples. The interatomic distances determined from Fourier transformation and fitting the data show Gd occupying the hafnium site in the HfO2 lattice, there was no clustering of Gd atoms, and the Gd ion retains monoclinic local symmetery for all levels of doping. Current as a function of voltage experiments identified the films as having poor diode characteristics with high leakage current in the forward bias region. However, a proper bias (0.5 V) for the purpose of neutron detection was identified and applied across the diodes. Using a high, non-varying neutron flux in a nuclear reactor, Gd doped HfO2 was able to be used in a detection system and displayed the ability to detect neutrons.