Scanning electron microscopy (SEM) is an electron microscopy technique in which a tiny beam of electrons is scanned across the surface of a sample. A high-resolution 3D image of the sample surface is generated when the electron beam strikes a metal-coated specimen and the electrons reflected (back-scattered) or given-off (secondary electrons) are detected.
Equipment:
Zeiss X 350 SEM (Ultrahigh resolution SEM with field-emission gun)
Hitachi SU8700 SEM (Ultrahigh resolution SEM/low vacuum variable pressure SEM)
Tousimis Critical Point Dryer, Cressington Sputter Coater, Leica ACE600 coaters to prepare samples for SEM
Sample Preparation:
Hitachi SU8700 variable pressure SEM – samples are not required to be coated
Hitachi SU8700 HRSEM and Zeiss XB350 SEM – samples are required to be dehydrated and coated
- Fixation
- Dehydration
- Critical point dry (complete dehydration)
- Mounting
- Sputter coating (with Gold and/or Platinum)
- SEM
Comparison of High-resolution SEM and VP SEM
| Zeiss XB350 Field emission (FE)-SEM | Htachi SU8700 Field emission (FE)-SEM | Hitachi SU8700 Variable pressure (VP)-SEM | |
| Resolution | Ultrahigh up to 0.7 nm | Ultrahigh up to 0.6 nm | |
| Electron Gun | Field emission schottky gun - very bright, tiny spot size, low voltage | Field emission schottky gun - very bright, tiny spot size, low voltage | Field emission schottky gun - very bright, tiny spot size, low voltage |
| Vacuum | Ultrahigh | Ultrahigh | Low 5-300 Pa |
| Sample Condition | Dry, coated with metal | Dry, coated with metal | Semi dry sample can be viewed No sample preparation is needed |
Publications:
Andrew, L. J., Gillman, E. R., Walters, C. M., Lizundia, E., & MacLachlan, M. J. (2023). Multi‐responsive supercapacitors from chiral nematic cellulose nanocrystal‐based activated carbon aerogels. Small, 19(34). https://doi.org/10.1002/smll.202301947
Bi, W., Gyenge, E., & Wilkinson, D. P. (2023). Crossover, volatilization, and adsorption of ammonium ions in a proton-exchange membrane electrolyzer in relation to electrochemical ammonia production. Chemical Engineering Journal, 478, 147359. https://doi.org/10.1016/j.cej.2023.147359
Cai, G., Zong, Z., Smith, K. J., & Upham, D. C. (2023). New Molten Metal Catalysts for CO2 and CH4 conversion to 2 : 1 H2 : Co syngas. Chemical Communications, 59(52), 8143–8146. https://doi.org/10.1039/d3cc02088f
Fleetwood, S. K., Bell, S., Jetter, R., & Foster, E. J. (2023). Plant-based, aqueous, water-repellent sprays for coating textiles. Soft Matter, 19(36), 7020–7032. https://doi.org/10.1039/d3sm00720k