二氧化锡薄膜的结构和光电性质分析-微电子学与固体电子学专业论文.docx

ABSTRACT SnO2, which is a transparent conducting oxide, is widely used as transparent electrode in solar cells, flat panel displays and defrost or anti-moist glasses. On the other hand, due to its high sensitivity in gas, heat and pressure, it is also commonly applied in fabricating sensors. As a direct wide band gap semiconductor, SnO2 exhibits a high exciton binding of 130 meV, thus is considered to be a promising candidate for ultraviolate photoelectric devices. In this work, undoped and doped (dopant is Mg or Al) SnO2 polycrystalline thin films were deposited by rf magnetron sputtering. The deposition parameters such as oxygen partial pressure (Opp) and substrate temperature were altered to obtain different series of SnO2 thin films. We analyzed the structure, optical and electrical properties of the films. The the influence of deposition parameters on the properties of the films were also carefully studied. The electronic transport property of SnO2 was investigated over a wide temperature range. From ~380 to ~2 K, the conduction mechanisms of thermally activated, nearest neighbour hopping, Mott VRH (variable range hopping) and ES VRH were observed in a sequence. The obtained activation energies (~30 and ~100 meV) in the thermally activated conduction indicates the main contributor of electrons in the nominally undoped SnO2 is intrinsic oxygen vacancies. Below ~80 K, the dominate conduction mechanism turns into VRH conduction. With an increase in the oxygen partial pressure in the deposition process, the disordered degree, crossover temperature from Mott VRH to ES VRH and density of states near Fermi level (regardless of electron-electron interaction) also increased. The structural analysis shows that the preferred orientation, grain size and surface morphology of the films can be effectively tuned by varying oxygen content in the sputtering gas. The grain size and surface roughness decreased with increasing Opp. In the undoped SnO2 thin films, (001)、(100