Fotoenergetikada nanostrukturali yarimo‘tkazgich materiallar II xalqaro ilmiy anjumani

Fotoenergetikada nanostrukturali yarimo‘tkazgich materiallar

II xalqaro ilmiy anjumani 
 
19-20 noyabr 2021 yil 
131 
10
3
Ohm

cm. The measurements were carried out using an infrared spectrometer 
IRS-21 at a temperature of 77
K
. Dark photoconductivity in samples with 

= 10
3
Ohm

cm started at h

= 0.3 
eV
and had a small peak at h

= 0.38 
eV
. In 
i
-type 
samples with 

= 10
5 
Ohm

cm, the dark spectrum was monotonic. In these samples, 
the dark photoconductivity increased monotonically starting with 
h

 

0.5 
eV
. 
The present paper reports the results of a study of the photoconductivity 
spectrum of silicon samples doped with sulfur under dark conditions and under 
constant illumination in forward and reverse connect modes and, accordingly, the 
curves of dependence of the current in the samples on the energy of incident 
photons are presented. 
The authors investigated the photoconductivity spectra of initial 
p
-type 
silicon samples with 

=1 Ohm

cm (boron-doped silicon), doped with sulfur in 
dark and under illumination (source is a conventional 2
V
incandescent lamp)
under forward and reverse switching modes. 
Photoconductivity measurements of samples doped with S were carried out 
on IRS-21 spectrometer equipped with a cryostat, which allowed studying the 
photoconductivity in a wide temperature range (
T
=77–350 
K
). To study only the 
impurity-induced photoconductivity, a double filter system fabricated of a polished 
single-crystal silicon plate was used, which was installed in front of the cryostat 
window after IRS-21 lighting source. 
An ohmic contact of InGa (97% -3%) was deposited on the front surface 
with 
p
-type conductivity, and a contact made of InSn (52% -48%) was applied on 
the back surface with 
n
-type conductivity. The sample appeared to be sensitive to 
light. 
Photoconductivity in dark conditions and under light were recorded 
according to the standard diagram. The amperage were recorded with a SH300-
type universal nanoammeter. 
Behavior of sulfur in silicon is characterized by the ionization energy 
E
i 
that 
varies in a large diapason as reported by different authors [8]. 
The authors in [7] explain such an ambiguity in the values of the ionization 
energy and the ionization energy band in the region 
h

= 0.28–0.38 
eV
by the fact 
that sulfur in silicon is a relatively shallow single-charged donor, and the formation 
of deeper impurity levels can be associated with the fact that that sulfur relatively 
easily forms associations of closely spaced singly charged atoms and the ionization 
energies of electrons are determined not only by the ionization potential of an 
isolated sulfur atom, but also by the Coulomb interaction of the ions included in 
the association. 

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