Scanning tunneling microscope light emission spectra of polycrystalline and

✍ Scribed by Y. Uehara; M. Kuwahara; S. Katano; S. Ushioda

• Publisher: Elsevier Science
• Year: 2009
• Tongue: English
• Weight: 865 KB
• Volume: 149
• Category: Article
• ISSN: 0038-1098
• DOI: 10.1016/j.ssc.2009.07.051

✦ Synopsis

We have observed scanning tunneling microscope light emission (STM-LE) spectra of Ge 2 Sb 2 Te 5 and Sb 2 Te 3 . Although these chalcogenide alloys exhibit band gaps less than 0.5 eV, the STM-LE was observed with a narrow spectral width at a photon energy of 1.5 eV for both materials. By analyzing its bias voltage, polarity, and temperature dependencies combined with recently reported theoretical electronic structures, we concluded that the STM-LE is excited by electronic transitions taking place in the local electronic structure having a direct gap-like shape with a band gap of 1.5 eV, commonly found in the electronic structures of both materials.