Electronic punch on the thiolated-Au films by atomic force microscopy.
To measure the thickness of SAMs, ellipsometry using a p-polarized laser beam is commonly used, which provides indirect information on the entire surface. Herein, a direct method for estimating the thickness of multilayered thiolated-Au films using atomic force microscopy (AFM) oxidation is described. When a bias voltage is applied to thiolated-Au films, the sulfur-gold bond is readily cleaved via a desorption procedure, and the nano-explosion through electron tunneling occurs at the nano-contact between the probe tip and surface. A multi-step uncovered layer is obtained, which can be used to estimate the thickness of each layer (organic and gold). This procedure is referred to as "electronic punch" of AFM, and is applicable to thiolated-Au films.
Kim
Younghun
Y
Department of Chemical Engineering, Kwangwoon University, Seoul 139-701, Korea.
Lee
Jeongjin
J
Yi
Jongheop
J