Representative tin sulfide compounds, tin monosulfide (SnS) and tin disulfide (SnS) are strong candidates for future nanoelectronic devices, based on non-toxicity, low cost, unique structures and optoelectronic properties. However, it is insufficient for synthesizing of tin sulfide thin films using vapor phase deposition method which is capable of fabricating reproducible device and securing high quality films, and their device characteristics. In this study, we obtained highly crystalline SnS thin films by atomic layer deposition and obtained highly crystalline SnS thin films by phase transition of the SnS thin films. The SnS thin film was transformed into SnS thin film by annealing at 450 °C for 1 h in HS atmosphere. This phase transition was confirmed by x-ray diffractometer and x-ray photoelectron spectroscopy, and we studied the cause of the phase transition. We then compared the film characteristics of these two tin sulfide thin films and their switching device characteristics. SnS and SnS thin films had optical bandgaps of 1.35 and 2.70 eV, and absorption coefficients of about 10 and 10 cm in the visible region, respectively. In addition, SnS and SnS thin films exhibited p-type and n-type semiconductor characteristics. In the images of high resolution-transmission electron microscopy, SnS and SnS directly showed a highly crystalline orthorhombic and hexagonal layered structure. The field effect transistors of SnS and SnS thin films exhibited on-off drain current ratios of 8.8 and 2.1 × 10 and mobilities of 0.21 and 0.014 cm V s, respectively. This difference in switching device characteristics mainly depends on the carrier concentration because it contributes to off-state conductance and mobility. The major carrier concentrations of the SnS and SnS thin films were 6.0 × 10 and 8.7 × 10 cm, respectively, in this experiment.

A sliding mode wheel slip controller is the subject of this paper. The proposed wheel slip controller was based on a quarter-car model and a friction force observer was applied to ensure the robustness of the controller with respect to the estimation error. It was applied to a non-linear full vehicle model. This controller showed good longitudinal performance in tracking reference slip ratio regardless of modelling errors and disturbances. However, when cornering was combined with braking or there was a yaw moment disturbance due to a í-split road, it was diYcult to achieve the desired performance using this controller. In this case, lateral motion must be considered in maintaining the control of the vehicle. A yaw moment control method using the modi ed reference yaw rate was investigated. The eVectiveness of this control theory was veri ed through simulations of emergency manoeuvres using a developed non-linear full vehicle Simulink model.

Tin dioxide (SnO2) thin films were deposited by atomic layer deposition (ALD) using tetrakis(dimethylamino)tin {[(CH3)2N]4Sn} and various concentrations of ozone (O3) at 200 °C. In order to characterize SnO2 thin films, the growth rate, thin film crystallinity, surface roughness, chemical bonding state, and electrical and optical properties were investigated. The growth rate of SnO2 increased slightly when the O3 concentration was increased. However, the growth rate was almost saturated above 300 g/m3 concentration of O3. Also, the x-ray diffraction patterns of SnO2 thin films become sharper when the O3 concentration increased. Specifically, the (101) and (211) peaks of SnO2 improved. In addition, the defects of the SnO2 thin films such as oxygen vacancy and hydroxyl group are related to the O3 concentration that was observed via x-ray photoelectron spectroscopy. As the O3 concentration is higher than 300 g/m3, the electrical Hall resistivity and mobility saturated 3.6 × 10−3 Ω cm and 9.58 cm2/V s, respectively. However, the carrier concentration slightly decreased to 3.22 × 1020 cm−3. It is assumed that the oxygen vacancies were filled with a high O3 concentration at ALD reaction. The optical bandgaps were larger than 3.5 eV, and the transmittance of all SnO2 thin films exceeded 90%. The O3 concentration below 200 g/m3 in the ALD process of SnO2 thin films is considered to be one of the factors that can affect the crystallinity, chemical bonding, and electrical properties.

No abstract

The authors investigated the effective Schottky barrier heights of metal and silicon contacts after insertion of insulator layers with different conduction band offsets. A decrease in Schottky barrier height after insertion of an insulator layer was observed. In particular, the Schottky barrier height of metal/semiconductor contacts was lowest when a ZnO layer was inserted compared to the other insulator layer types, because the conduction band offset between ZnO and silicon was the lowest among those measured. The authors also investigated current density as a function of the thickness of the insulator and doping concentration of silicon.