Fast exothermic processes in porous silicon

The Burning Rate of Energetic Films of Nanostructured Porous Silicon

“…Lazaruk et al7 demonstrated a linear relationship between the thickness of the pSi layer (loaded with potassium nitrate) and the optical intensity of the resulting explosion. Lazarouk et al10 suggested that the minimum thickness for an energetic reaction between pSi and potassium nitrate was 15 μm. However, no data was presented in this or other literature that suggested an upper limit beyond which no velocity advantage is observed.…”

“…They found that, on freshly prepared surfaces, the explosive reaction would occur spontaneously at temperatures as low as 4.2 K. On aged pSi, the surface was stable enough to not explode spontaneously, but could be initiated as a result of mechanical impact or exposure to an ultraviolet laser. Research has accelerated since this work and numerous groups have found that various oxidizing agents are capable of producing strong explosive reactions 6–12. These agents typically include sodium perchlorate, aluminium or potassium nitrates, sulphur, potassium permanganate, and potassium dichromate, with different groups reporting varying degrees of success with these oxidisers:6–12 sodium perchlorate is reported as delivering the most violent reaction, with oxidizing agents yielding weaker or even insignificant reactions 8, 11.…”

The influence of pore size and oxidizing agent on the energetic properties of porous silicon

“…They found that on freshly prepared surfaces, the explosive reaction would occur spontaneously at temperatures as low as 4.2 K. On aged pSi, the surface was stable enough to not explode spontaneously, but could be initiated as a result of mechanical impact or heating by an ultraviolet laser. Research has accelerated since these works, and numerous groups have found that various oxidising agents are capable of producing the strong explosive reactions [8][9][10][11][12][13][14][15][16][17]. These agents typically include sodium perchlorate, aluminium or potassium nitrates, sulphur, potassium permanganate and potassium dichromate, with different groups reporting varying degrees of success with these agents.…”

Sensitiveness of Porous Silicon‐Based Nano‐Energetic Films

“…The applied current was pulsed with a6 6% duty cycle( 10 seconds on, 5seconds off), for ad esired numbero fc ycles, at current densities of either 22.5 or 45 mA cm À2 .P revious work has determined that these etching conditions produce pSi surfaces with pore sizes of 3.6 AE 1.4 nm and ap orosity of 64.7 AE 0.5 % [ 18].W afers were washedw ith ethanol and acetonep rior to and after etching, and dried in as tream of nitrogen gas. All samples were stored in ad esiccator when not being handled.F or all investigations reported herein the pSi layer remainsa ttached to the supporting Si wafer.I nt his configuration,o nly the pSi forms the reactive material and the supporting wafer takes no part in the reaction [19].…”