Charge injection and tunneling mechanism of solid state reaction silicon nanocrystal film

Solid state reaction silicon nanocrystals (Si nc's) of an average size of 10 nm have been synthesized. Charge transport characteristics have been investigated as a function of temperature and voltage. From 305 to 400 K, it is found that space-charge-limited current (SCLC), with an exponential distribution of trapping states, dominates the conduction mechanism. High resolution transmission electron microscope images indicate that microscopic structural defects, such as dislocations, are present in this solid state reaction Si nc. These defects are a possible source of trapping states as described in the SCLC model. Using this model, a trap density of N_t=1.46 × 10 ¹⁸ cm^-3 and a characteristic trap temperature T _t=2057 K can be extracted. The trap density is two orders of magnitude greater than the Si nc density, showing that the structural defects in Si nc, such as dislocations and grain boundaries, are capable of trapping more carriers in a single solid state reaction Si nc.