The interface between the insulator and the phosphor layers in TFEL devices is important for charge transfer and luminescent characteristics. In this study the XPS of SrS/α-SiO~2 interface was measured. The concentration of each element and their chemical forms were analysed by Sr3d, S2p, Si2p and O1s core levels electron spectroscopy. The results indicated that Sr^2^+ and S^2^- diffused into the SiO~2 layer. O vacancies and strontium oxide were found in the SiO~2 layer. The primary electrons for TFEL devices can come from these interface states.

Key words: SULFIDE, STRONTIUM COMPOUNDS, SILICON DIOXIDE, INTERFACES, X-RAY PHOTOELECTRON SPECTROMETRY, CHEMICAL SHIFT, ELECTRONIC STATES, INTERFACE STATE, ELECTRONIC STRUCTURE, TRANSPORT