| AVS 60th International Symposium and Exhibition | |
| Nanometer-scale Science and Technology | Wednesday Sessions |
| Session NS+AS+BI+SP-WeM |
| Session: | Nanoscale Imaging and Microscopy |
| Presenter: | E. Dillon, Anasys Instruments |
| Authors: | E. Dillon, Anasys Instruments M. Lo, Anasys Instruments C. Prater, Anasys Instruments K. Kjoller, Anasys Instruments M. Belkin, University of Texas at Austin F. Lu, University of Texas at Austin |
| Correspondent: | Click to Email |
As current research focuses on shrinking the size of devices and the components that comprise these devices, the characterization of these systems becomes more and more challenging. The resolution of conventional IR spectroscopy techniques is diffraction limited to a practical resolution limit of ~ 3 µm. This length scale is too large to observe any potential nanoscale features on today’s devices. Atomic force microscopy (AFM) is a widely used nanoscale imaging technique that provides the user with a high spatial resolution topographic map of a sample surface. When combined; the resulting AFM-IR can provide the high resolution topographic maps commonly associated with AFM with the addition of high spatial resolution IR spectroscopy and IR imaging. Currently, AFM-IR spectroscopy has the ability to collect IR spectroscopic information below the diffraction limit with a lateral resolution of ~ 100 nm. However, there are still some limitations that prevent its use on many important nanoscale systems. One of the main limitations is the thickness of sample required for examination (> 100 nm). Overcoming these limitations has a dramatic impact by enabling widespread use of nanoscale IR spectroscopy for spatially resolved chemical characterization. The use of a quantum cascade laser (QCL) as the IR source significantly increases the sensitivity of AFM-IR. The QCL has repetition rates 1000 times higher than previous lasers used for AFM-IR. This allows the ability to pulse the laser at the resonant frequency of the AFM cantilever giving rise to a high IR sensitivity mode referred to as resonance enhanced infrared nanospectroscopy (REINS). Due to the increased IR sensitivity, less laser power is required to generate a spectrum, meaning samples that were too thin or easily damaged using previous AFM-IR techniques can now be easily examined. Using REINS we have been able to collect nanoscale IR spectra and perform chemical imaging on films as thin as 10 nm. These advances in AFM-IR allow for the characterization of samples from a wide variety of applications, including, organic photovoltaic materials, materials for energy generation and storage, cellular biology, development of advanced polymeric materials and integrated circuit devices.