The synthesis of III–V semiconductor nanoparticles using indium and gallium diorganophosphides as single-molecular precursors

Abstract

Novel routes to quantum dots of InP and GaP have been developed using the thermolysis of the corresponding metal diorganophosphide in hot 4-ethylpyridine, a polar, co-ordinating Lewis base. Investigations into the thermal decomposition mechanisms of M(P^tBu₂)₃ (M = Ga, In) suggested three major processes, two of which are temperature dependant; reductive elimination and β-hydrogen elimination, a third minor pathway (involving both of these processes in a single molecule), and the strain induced bond rupture leading to free-radical generation. This information has allowed us to prepare nanocrystals with a minimum of metal contamination. Similar experiments carried out in hot tri-n-octylphosphine oxide were unsuccessful; the nanocrystals obtained were poorly crystalline. Electron microscopy showed a mixture of amorphous and crystalline dots of ca. 7 nm diameter. The dots were polydispersed (standard deviation of ca. 18%).