We describe an apparatus for friction experiments on molecularly thin films carried out with the quartz crystal microbalance technique (QCM) in ultrahigh vacuum (UHV) and at a temperature as low as 4 K. Through the implementation in the UHV chamber of standard cryogenic procedures, the temperature of the quartz can be controlled with a resolution better than 5 mK below 10 K. The main chamber is provided with a stainless steel jacket that allows a quick change of the various temperature inserts (cryocooler head, liquid nitrogen insert, Peltier-cell stage, etc.) that span the working range 4-400 K, without ever breaking the vacuum. The crystal mounting is compatible with UHV conditions and with the Omicron standard and guarantees a good thermal and electrical contact over the entire temperature range. Once inserted in the copper sample holder, the quartz frequency and amplitude stabilities are found to be as good as the best recorded values achieved with QCMs mounted in standard high-vacuum, liquid bath cryostats. This apparatus can also be used for general QCM investigations in surface science, like the determination of film growth in deposition and sputter processes, the stoichiometry of submonolayer oxide films, and the measurement of adsorbate sticking probability. (C) 2005 American Institute of Physics.
Ultrahigh vacuum apparatus for quartz crystal microbalance measurements in the temperature range 4–400 K
BUATIER DE MONGEOT, FRANCESCO;
2005-01-01
Abstract
We describe an apparatus for friction experiments on molecularly thin films carried out with the quartz crystal microbalance technique (QCM) in ultrahigh vacuum (UHV) and at a temperature as low as 4 K. Through the implementation in the UHV chamber of standard cryogenic procedures, the temperature of the quartz can be controlled with a resolution better than 5 mK below 10 K. The main chamber is provided with a stainless steel jacket that allows a quick change of the various temperature inserts (cryocooler head, liquid nitrogen insert, Peltier-cell stage, etc.) that span the working range 4-400 K, without ever breaking the vacuum. The crystal mounting is compatible with UHV conditions and with the Omicron standard and guarantees a good thermal and electrical contact over the entire temperature range. Once inserted in the copper sample holder, the quartz frequency and amplitude stabilities are found to be as good as the best recorded values achieved with QCMs mounted in standard high-vacuum, liquid bath cryostats. This apparatus can also be used for general QCM investigations in surface science, like the determination of film growth in deposition and sputter processes, the stoichiometry of submonolayer oxide films, and the measurement of adsorbate sticking probability. (C) 2005 American Institute of Physics.
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
