Work function response of thin gold film surfaces to phosphine and arsine

The work function changes of thin gold films upon exposure to phosphine and arsine in the concentration range 20–80 parts per billion (ppb) concentrations were studied using the Kelvin probe method under ambient conditions. The work function of gold surfaces decreases significantly in the presence of these gases. This decrease is attributed to charge transfer from these hydride molecules to the gold surface through σ-bonding of their lone-pair electrons. Auger electron spectroscopy and secondary ion mass spectrometry were used to characterize the surface chemical components of thin gold films. The extraordinarily high sub-ppb sensitivity of the work function response for phosphine and arsine on gold surfaces under ambient conditions can be used to detect ultra-trace concentration of these toxic gases.