Papers by Author: Saleh Thaker Mahmoud

Abstract: The electrical and optical characteristics of indium doped Se₂Sb₂Te₆ phase-change alloy are studied. It is found that adding indium to Se2Sb2Te6 alloy (In_0.3Se₂Sb₂Te₆) increased the crystallization temperature and reduced the electrical conduction activation energy. The capacitance-temperature measurements showed a drastic change in the capacitance of the modified film when the temperature approaches the crystallization temperature, and eventually the capacitance becomes negative and nonlinear. The negativity and nonlinearity in the capacitancevoltage dependence can be attributed to the growth of conductive crystalline islands by increasing the temperature.

Abstract: Composites of copper–tin (Cu_xSn_1-x) nanoclusters were synthesized using the magnetron dc sputtering gas–condensation technique. Targets with controlled ratios of Sn to Cu were used to produce Cu_xSn_1-x with different compositions. The effects on the nanocluster size and yield of the sputtering discharge power, inert gas flow rate, and aggregation length were investigated using a quadrupole mass filter. The sputtering discharge power was optimized to maximize the nanocluster yield. The results show that as the inert gas flow rate increases the nanocluster size increases and then decreases. These dependences could be understood in terms of the dominant nanocluster production mechanisms. This work demonstrates the ability of controlling the Cu_xSn_1-x nanoclusters’ size and composition by optimizing the source operation conditions.