UHV characterization of ambient-dosed hydrogen-terminated Si(0 0 1)

We report ultra-high vacuum characterization of a high-molecular weight pentiptycene-based copolymer deposited from solution onto H-terminated Si(0 0 1) surfaces under ambient conditions. We found that NMR-grade deuterated chloroform was the best choice of solvent to preserve the cleanliness of the sample, resulting in the lowest sample C and O contamination as determined by AES and STM. The H-terminated Si(0 0 1) – 2 × 1 surface proved to be an excellent metrology tool for measuring the molecular features of the polymer with nanometer resolution. Atomically resolved STM images of single polymer molecules were obtained. The average periodicity along the polymer chain was 1.26 nm, with the width of the polymer varying between 0.98 nm and 1.5 nm. Kinks observed along the polymer chain are consistent with a reduction of the polymer backbone from alkyne to alkene.