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Educational Research in Universal Sciences issn: 181-3515 volumeBog'liq 4 Educational Research in Universal Sciences ISSN 2181-3515 VOLUME 2 SPECIAL ISSUE 12 2023117
Kalit so‘zlar: geterotuzilish, nanofaza, tarmoqli boʻshliq, nanotuzilish,
nanokristal qatlam, ion implantatsiyasi, yuza tuzilishi, silisid, oʻtish qatlami.
At present, much attention is paid to the study of the optical and electronic
properties of semiconductors with nanophases and nanofilms on the surface layers. Of
particular interest are studies related to the change in the properties of silicon with a
decrease in its size to several nanometers, as well as studies aimed at changing the
properties of Si nanofilms under various influences (atomic adsorption, ion and
electron bombardment, oxidation). It was shown in [1–3] that an increase in porosity
and, therefore, a decrease in the size and change in the shape of silicon nanophases
leads to an increase in the light absorption edge towards higher energies, which is
explained by an increase in the band gap Eg. The largest increase in Eg (up to 1.7 eV)
is observed when the size of Si nanocrystalline phases is ≤ 3–4 nm [2, 5]. An increase
in Eg to 1.9 eV is also observed in the case of the formation of thin amorphous silicon
films [5]. Therefore, the amorphous silicon/nanocrystalline silicon system is a
promising material for the development of high efficiency solar cells [6-8].
It is shown that the band gap Е
g
of nanoscale phases of the MeSi
2
/Si and GaMeAs
types is noticeably larger than Е
g
of bulk MeSi
2
and GaMeAs films. The sizes of
nanostructures at which quantum-size effects begin to appear are estimated. When
monatomic single-crystal semiconductors (Si, Ge) are bombarded under conditions of
ultrahigh vacuum with ions of inert gases, the composition of ion-bombarded layers
practically does not change, and all changes in properties are determined only by
disordering of the near-surface layers. However, the influence of the formation of
disordered phases and layers on the band structure has not yet been practically studied,
and the electrophysical and optical properties of Si have been practically not studied.
The results of such studies are of practical and scientific interest.
Therefore, the main purpose of this work is to study the effect of the formation of
nanosized phases in the near-surface region of Si (111) single crystals upon
bombardment with Ar
+
and Ni
+
ions with E
0
= 0.5 – 2 keV, energy band parameters,
electrical and optical properties.
Single-crystal samples of Si (111) with dimensions of 10100.5 mm were used
as the object of study. Thermal treatment, bombardment with Ar+ and Ni+ ions and
studies using the methods of Auger electron spectroscopy (OES), ultraviolet
photoelectron spectroscopy (UVES), measurements of the energy and quantum yields
of photoelectrons were carried out in the same experimental device at vacuum Р 10
-
7
Pa. The energy of Ar
+
and Ni
+
ions varied within E
0
= 0.5 – 2 keV, and their dose was
D = 10
14
– 10
17
cm
-2
. Before ion bombardment, the Si surface was degassed at T = 1200
K for 4–5 hours in combination with short-term heating up to T = 1500 K at a vacuum
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