Image of the Month

October 2007

Near-field scanning optical microscopy of the InGaN islands

Microscope:
Veeco Bioscope

Controls:
RHK Technology SPM 1000 featuring XPMProTM

Description:
Near-field signal maps of the InGaN islands were collected under excitation by two different visible laser wavelengths, 633 nm (Fig. B) and 532 nm (Fig. C). Scattered near-field measurements indicate that the as-grown InGaN islanded film may exhibit both inhomogeneous In composition and strain-induced changes that affect the optical signal at 633 nm and 532 nm.

Apertureless near-field microscope is based on the commercial AFM controlled by the SPM 1000 controller. Linearly polarized radiation from a HeNe laser (633 nm) or frequency-doubled Nd:YAG cw laser (532 nm) is directed into a microscope objective lens and focused onto the sample at an angle of 30° with respect to the sample surface. Back scattered radiation from the tip-sample junction is collected by the same objective lens. Optical and topography images of the sample are recorded simultaneously.

Courtesy of: Larissa V. Stebounova, Yaroslav E. Romanyuk, Dongxue Chen, and Stephen R. Leone

Lawrence Berkeley National Laboratory & University of California, Berkeley