Fotoenergetikada nanostrukturali yarimo‘tkazgich materiallar II xalqaro ilmiy anjumani

Fotoenergetikada nanostrukturali yarimo‘tkazgich materiallar

II xalqaro ilmiy anjumani 
 
19-20 noyabr 2021 yil 
426 
Experimental data show that during heat treatment of samples in the 
temperature range 
T
=700÷900 °C, the clusters are ordered. This phenomenon 
cannot be explained without the displacement of the clusters from their initial 
states, i.e. their diffusion in the silicon crystal lattice. Thus, a very interesting and 
new physical phenomenon is observed - the diffusion of clusters, which makes it 
possible to control their state in the silicon crystal lattice. 
Fig.1. Composition of clusters of impurity niked atoms 
To clarify the diffusion mechanism of clusters of impurity nickel atoms, it 
was necessary to determine the composition of the clusters obtained. The 
composition of the clusters of impurity nickel atoms was determined using the 
modern method of energy dispersive X-ray spectroscopy EDS. As shown by the 
results of the study, such clusters contain Ni → 7,5 %, O
2
→ 7,7 %, Si → 71,3 % 
(
Fig.1
). This means that the cluster is a piece of silicon enriched with nickel and 
oxygen atoms. Therefore, it can be assumed that during the formation of clusters, 
the crystal structure of silicon is not significantly destroyed during the formation of 
a cluster. The cluster consists of interstitial nickel and oxygen atoms, which form a 
sublattice in the crystal lattice of silicon with a specific structure. This makes it 
possible to explain the diffusion of clusters of impurity nickel atoms with a very 
high diffusion coefficient [4].
Since nickel atoms are bonded to oxygen atoms in clusters, being in 
interstitial positions in the lattice at a certain temperature, they move 
synchronously with all cluster atoms. This allows not only to provide a 
thermodynamically more favorable state of clusters in the silicon lattice, but also 
provides a low free energy, i.e. the most favorable state of the system. This is 
evidenced by the appearing peaks on the X-ray diffraction pattern, which indicate 
that the region around the cluster of nickel atoms has a crystalline structure. 
The diffusion coefficient of clusters of impurity nickel atoms was calculated, 
taking into account their density (
S
~ 10
6
cm
2
) and the distance between them. 
Then the diffusion coefficient of the cluster is 
D
≈ 1.2·10
-9
cm
2
/s, although this 
value is almost 1,5÷2 orders of magnitude less than the diffusion coefficient of 
nickel atoms at a temperature of 
T
=800 °C, it shows that clusters of impurity nickel 

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