[3Ga01-10] Surface Science(SS1) Physical Property

[3Ga07] STM-induced luminescence mediated via quantum well states of indium ultra-thin films

*Kenta Kuroishi¹, Hiroshi Okuyama¹, Shinichiro Hatta¹, Tetsuya Aruga¹ (1. Graduate school of Kyoto University)

We performed the experimental studies on indium films with 2-8 ML prepared on Si(111) using by STM. STM observed atomically flat surfaces with different structures in the 2–4 ML range, while thicker films displayed the same structure. Conductance measurements at each film showed several peaks whose positions depended on the film thickness and they are assigned to quantum well states originated from sp electron in indium. Light emission estimated by tunneling electrons was also measured. Luminescence from the films with positive sample bias voltages exhibited different features from bulk metal surface in which the photon energy depends on both film thickness and bias voltage. This process is attributed to the radiative decay of the junction plasmon excited by inelastic tunneling to the QWS.