Abstract
We measured the current passing between a sample and a scanning tunneling microscope (STM) tip under conditions of X-ray irradiation. As shown in our previous reports, this STM tip current originated from electron emission on the sample surface. For high precision STM tip current measurement, we applied an X-ray modulation technique using an X-ray chopper and a lock-in amplifier. X-rays modulated by the X-ray chopper irradiated the sample surface of the STM, and the STM tip current was detected using the lock-in amplifier. The largest and most stable output from the lock-in amplifier was obtained under the experimental conditions of low modulation frequency (∼10 Hz), strong X-ray intensity, and high STM bias voltage. Compared with measuring the STM tip current directly without the modulation technique, the precision of this measurement is threefold better.
| Original language | English |
|---|---|
| Pages (from-to) | 2028-2032 |
| Number of pages | 5 |
| Journal | Japanese Journal of Applied Physics, Part 1: Regular Papers and Short Notes and Review Papers |
| Volume | 37 |
| Issue number | 4 SUPPL. A |
| DOIs | |
| Publication status | Published - 1998 Apr |
| Externally published | Yes |
Keywords
- Electron emission
- Modulation frequency
- Scanning tunneling microscope
- X-ray excited current
- X-ray irradiation
ASJC Scopus subject areas
- Engineering(all)
- Physics and Astronomy(all)