Porous gallium arsenide with arsenic clusters

It is for the first time that the possibility is demonstrated of preparing gallium arsenide with arsenic clusters under conditions of annealing of its porous layers obtained by electrochemical etching. It is found that the clusters are concentrated in porous layer barriers, their size ranges from 1 to 10 nm, and the density reaches 4 x 10(18) cm(-3). Under conditions of annealing in the temperature range from 400 to 600 degrees C, an improvement in the structure quality of the porous layer is observed, and the lattice parameter (reduced for this layer) increases to approach a value characteristic of a single crystal. When highly alloyed substrates of the n-type are used, the inversion of the type of conductivity is observed in the surface part of the porous layer, which is due to the emergence of deep-lying acceptor centers. Thermal annealing leads to a narrowing of the inversion layer and to a more uniform distribution of electrically active centers over the porous layer thickness. (C) 2000 MAIK "Nauka/Interperiodica".