The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films
The influence of mechanisms of surface reflection of electrons on the ex-perimental electrical transport and thermoelectric properties of n-PbTe films on various substrates are considered based on the Fuchs–Sondheimer and Mayer models. The thickness dependence of conductivity, Hall coeffi-cient, and...
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Інститут металофізики ім. Г.В. Курдюмова НАН України
2017
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Цитувати: | The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films / M.A. Ruvinskii, O.B. Kostyuk, B.S. Dzundza, V.I. Makovyshyn // Наносистеми, наноматеріали, нанотехнології: Зб. наук. пр. — К.: РВВ ІМФ, 2017. — Т. 15, № 2. — С. 277-288. — Бібліогр.: 16 назв. — англ. |
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irk-123456789-1331862018-05-22T03:03:11Z The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films Ruvinskii, M.A. Kostyuk, O.B. Dzundza, B.S. Makovyshyn, V.I. The influence of mechanisms of surface reflection of electrons on the ex-perimental electrical transport and thermoelectric properties of n-PbTe films on various substrates are considered based on the Fuchs–Sondheimer and Mayer models. The thickness dependence of conductivity, Hall coeffi-cient, and Seebeck coefficient of films based on PbTe are investigated. As shown, for the films on glassceramic substrates, mechanism of completely diffuse scattering of carriers (p ≈ 0) are implemented, and for the films obtained on fresh mica chips, mixed mechanism of specular–diffuse scat-tering of carriers is realized (scattering coefficient p ≈ 0.4). Вивчено вплив механізмів поверхневого відбивання електронів на експериментальне електроперенесення та термоелектричні властивості плівок n-PbTe на різних підкладинках на основі моделів Фукса–Сондхаймера та Маєра. Досліджено залежність від товщини провідности, Голлового коефіцієнта і Зеєбекового коефіцієнта плівок на основі PbTe. Показано, що для плівок на ситалових підкладинках реалізується механізм повністю дифузного розсіяння носіїв заряду (p ≈ 0), а для плівок, одержаних на свіжоприготовлених лоснякових кристаликах, — мішаний дзеркально-дифузний механізм розсіяння носіїв (коефіцієнт розсіяння p ≈ 0,4). Изучено влияние механизмов поверхностного отражения электронов на экспериментальный электроперенос и термоэлектрические свойства плёнок n-PbTe на различных подложках на основе моделей Фукса–Сондхаймера и Майера. Исследована зависимость от толщины прово-димости, коэффициента Холла и коэффициента Зеебека плёнок на ос-нове PbTe. Показано, что для плёнок на ситалловых подложках реали-зуется механизм полностью диффузного рассеяния носителей заряда (p ≈ 0), а для плёнок, полученных на свежеприготовленных слюдяных кристалликах, — смешанный зеркально-диффузный механизм рассея-ния носителей (коэффициент рассеяния p ≈ 0,4). 2017 Article The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films / M.A. Ruvinskii, O.B. Kostyuk, B.S. Dzundza, V.I. Makovyshyn // Наносистеми, наноматеріали, нанотехнології: Зб. наук. пр. — К.: РВВ ІМФ, 2017. — Т. 15, № 2. — С. 277-288. — Бібліогр.: 16 назв. — англ. 1816-5230 PACS: 68.35.Ct, 68.37.Ps, 73.50.Bk, 73.50.Lw, 81.07.Bc, 84.60.Rb, 85.80.Fi http://dspace.nbuv.gov.ua/handle/123456789/133186 en Наносистеми, наноматеріали, нанотехнології Інститут металофізики ім. Г.В. Курдюмова НАН України |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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description |
The influence of mechanisms of surface reflection of electrons on the ex-perimental electrical transport and thermoelectric properties of n-PbTe films on various substrates are considered based on the Fuchs–Sondheimer and Mayer models. The thickness dependence of conductivity, Hall coeffi-cient, and Seebeck coefficient of films based on PbTe are investigated. As shown, for the films on glassceramic substrates, mechanism of completely diffuse scattering of carriers (p ≈ 0) are implemented, and for the films obtained on fresh mica chips, mixed mechanism of specular–diffuse scat-tering of carriers is realized (scattering coefficient p ≈ 0.4). |
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Article |
author |
Ruvinskii, M.A. Kostyuk, O.B. Dzundza, B.S. Makovyshyn, V.I. |
spellingShingle |
Ruvinskii, M.A. Kostyuk, O.B. Dzundza, B.S. Makovyshyn, V.I. The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films Наносистеми, наноматеріали, нанотехнології |
author_facet |
Ruvinskii, M.A. Kostyuk, O.B. Dzundza, B.S. Makovyshyn, V.I. |
author_sort |
Ruvinskii, M.A. |
title |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films |
title_short |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films |
title_full |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films |
title_fullStr |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films |
title_full_unstemmed |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films |
title_sort |
influence of surface on scattering of carriers and kinetic effects in n-pbte films |
publisher |
Інститут металофізики ім. Г.В. Курдюмова НАН України |
publishDate |
2017 |
url |
http://dspace.nbuv.gov.ua/handle/123456789/133186 |
citation_txt |
The Influence of Surface on Scattering of Carriers and Kinetic Effects in n-PBTE Films / M.A. Ruvinskii, O.B. Kostyuk, B.S. Dzundza, V.I. Makovyshyn // Наносистеми, наноматеріали, нанотехнології: Зб. наук. пр. — К.: РВВ ІМФ, 2017. — Т. 15, № 2. — С. 277-288. — Бібліогр.: 16 назв. — англ. |
series |
Наносистеми, наноматеріали, нанотехнології |
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first_indexed |
2025-07-09T18:38:50Z |
last_indexed |
2025-07-09T18:38:50Z |
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1837195678843928576 |
fulltext |
277
PACS numbers: 68.35.Ct, 68.37.Ps, 73.50.Bk, 73.50.Lw, 81.07.Bc, 84.60.Rb, 85.80.Fi
The Influence of Surface on Scattering of Carriers
and Kinetic Effects in n-PBTE Films
M. A. Ruvinskii, O. B. Kostyuk, B. S. Dzundza, and V. I. Makovyshyn
Vasyl Stefanyk Precarpathian University,
Shevchenko Str., 57,
76018 Ivano-Frankivsk, Ukraine
The influence of mechanisms of surface reflection of electrons on the ex-
perimental electrical transport and thermoelectric properties of n-PbTe
films on various substrates are considered based on the Fuchs–Sondheimer
and Mayer models. The thickness dependence of conductivity, Hall coeffi-
cient, and Seebeck coefficient of films based on PbTe are investigated. As
shown, for the films on glassceramic substrates, mechanism of completely
diffuse scattering of carriers (p0) are implemented, and for the films
obtained on fresh mica chips, mixed mechanism of specular–diffuse scat-
tering of carriers is realized (scattering coefficient p0.4).
Вивчено вплив механізмів поверхневого відбивання електронів на екс-
периментальне електроперенесення та термоелектричні властивості
плівок n-PbTe на різних підкладинках на основі моделів Фукса–
Сондхаймера та Маєра. Досліджено залежність від товщини провіднос-
ти, Голлового коефіцієнта і Зеєбекового коефіцієнта плівок на основі
PbTe. Показано, що для плівок на ситалових підкладинках реалізуєть-
ся механізм повністю дифузного розсіяння носіїв заряду (p0), а для
плівок, одержаних на свіжоприготовлених лоснякових кристаликах, —
мішаний дзеркально-дифузний механізм розсіяння носіїв (коефіцієнт
розсіяння p0,4).
Изучено влияние механизмов поверхностного отражения электронов на
экспериментальный электроперенос и термоэлектрические свойства
плёнок n-PbTe на различных подложках на основе моделей Фукса–
Сондхаймера и Майера. Исследована зависимость от толщины прово-
димости, коэффициента Холла и коэффициента Зеебека плёнок на ос-
нове PbTe. Показано, что для плёнок на ситалловых подложках реали-
зуется механизм полностью диффузного рассеяния носителей заряда
(p0), а для плёнок, полученных на свежеприготовленных слюдяных
кристалликах, — смешанный зеркально-диффузный механизм рассея-
ния носителей (коэффициент рассеяния p0,4).
Наносистеми, наноматеріали, нанотехнології
Nanosistemi, Nanomateriali, Nanotehnologii
2017, т. 15, № 2, сс. 277–288
2017 ІÌÔ (Іíñòèòóò ìåòàëîôіçèêè
іì. Ã. Â. Êóðäþìîâà ÍÀÍ Óêðàїíи)
Надруковано в Óкраїні.
Фотокопіювання дозволено
тільки відповідно до ліцензії
278 M. A. RUVINSKII, O. B. KOSTYUK, B. S. DZUNDZA, and V. I. MAKOVYSHYN
Key words: size effect, thin film, lead telluride, thermoelectric properties.
Ключові слова: розмірний ефект, тонка плівка, телурид свинцю, тер-
моелектричні властивості.
Ключевые слова: размерный эффект, тонкая плёнка, теллурид свинца,
термоэлектрические свойства.
(Received 27 December, 2016)
1. INTRODUCTION
Lead telluride is well-known thermoelectric material for semicon-
ductor technology. Interest in research of it is not reduced over the
years due to the unique physical and chemical properties. As it is a
narrow semiconductor A4B6, so it is suitable for use in infrared la-
sers, optical detectors, and a thermoelectric material in average
temperatures (500–750 K) [1–3]. In thin films, due to the transi-
tion from 2D to 3D material, new dimensional effects occur in pro-
files of thermoelectric parameters.
Today the problem of calculation of the conductivity of thin films
is particularly relevant due to the rapid development of micro- and
nanoelectronics. Necessity of modern society in new energy sources
is accompanied by the rapid development of thermoelectric material.
Many studies considered that the scattering coefficient p for sem-
iconductor films is zero. However, this is not always true [4]. In
this paper, the influence of mechanism of surface reflection of elec-
trons on the thermoelectric properties of n-PbTe films on various
substrates is considered, and the thickness dependence of the See-
beck coefficient of films based on PbTe is investigated.
2. EXPERIMENTAL DETAILS
Films for research are obtained by vapour deposition of synthesized
material n-PbTe in a vacuum on the substrate of fresh chips (1000)
of mica-muscovite and sitall. The temperature of the evaporator was
Te870 K, and the temperature substrates Ts470 K. The thick-
nesses of films are set by the deposition time of 0.5–13 min and are
measured by microinterferometer MII-4.
Measurement of electrical parameters of films was carried out on
air at room temperature and at constant magnetic field on the au-
tomated device. It provides a process for measuring electrical pa-
rameters and initial registration and processing of data. Measured
sample had four Hall contacts and two current contacts. As the
ohmic contacts, a silver film was used. The current through the
THE INFLUENCE OF SURFACE ON SCATTERING OF CARRIERS IN n-PBTE 279
sample was 1 mA. The magnetic field was directed perpendicular-
ly to film surface. The induction of magnetic field was 1.2 Tesla.
For measurements of the Seebeck coefficient S, an integral meth-
od was used. One end of film had a constant temperature, and the
temperature of other end was changed. The ends of film were at-
tached to the massive copper plates to provide a constant tempera-
ture. For the measurement of temperature, platinum thermoresis-
tors were used. The sign of RH and S define type of carriers.
Dependences of conductivity , Hall coefficient RH, mobility ,
Seebeck coefficient S on the thickness of n-PbTe films is shown in
Figs. 1–8. Calculations of the (d), RH(d), (d), and S(d) dependenc-
es were performed with the use of mathematical package Maple 18.
3. ELEMENTS OF THEORY
The thin film has many sources of scattering of electrons. In our
paper, the size effects associated with scattering on the outer sur-
faces of film are considered. Fuchs and Sondheimer examined the
dependence of the current density j(z) on the film thickness d in de-
tail in works [5, 6]. Conductivity of film is determined from the
kinetic Boltzmann equation, taking into account boundary condi-
tions according to [5]:
3 5
1
3 3 1 1
1 exp
8 2
b
kt dt
k k t t
, (1)
where b—electrical conductivity of bulk samples, dimensionless
thickness equals to the film thickness divided to the length of the
average free path of electrons l:
k d l . (2)
For the limiting case of k1 (thick film), we obtain [6]:
1
3
1 1
8
b
p
k
( 1k ). (3)
For quite thin films (k1),
3 1 1
ln
4 1
b
p
k
p k
(k1). (4)
Here, p—the scattering coefficient (i.e., probability of specular re-
flection); 0 1p . When p0, it is a diffuse reflectance; p1
corresponds to a pure specular reflection; and if 0 1p , there is
a mixed specular–diffuse reflection. The case of a massive film is
280 M. A. RUVINSKII, O. B. KOSTYUK, B. S. DZUNDZA, and V. I. MAKOVYSHYN
realized with d .
The Fuchs–Sondheimer model is based on the assumption that the
statistical properties of the upper and lower surfaces of film can be
described by the same parameter p. However, by the example of
gold films, Lucas [7] experimentally showed that the scattering pro-
cesses on surfaces vary independently. In work [8], it was suggested
that the conductivity of film is characterized by two parameters:
scattering at the interface of film and free surface, p, and scatter-
ing at the interface of film and substrate, q. For the thick films,
equation for has the form:
1
3
1 1
8 2
b
p q
k
(k1). (5)
Let us consider the manifestation of size effect in dependence of
Hall coefficient RH on thickness in case of directional magnetic field
perpendicular to the surface of film and the current direction.
Within the Sondheimer model, Hall coefficient can be determined
from the following equation [6]:
2
14 1 1
ln
3 1
H Hb
p
R R k
p k
(k1). (6)
It should be mentioned that Sondheimer considered only the re-
gion of small k, because the Hall coefficient is mainly affected by
the external surface of scattering at low thicknesses.
In Ref. [9], the analytical expression for the Hall coefficient is
given and relatively easy leads to numerical evaluation of RН:
1
2 2 2
H Hb
R R B A B
, (7)
where l D —reduced mean free path (D—Larmor radius),
2
2 2 2 1 2
2 3 1
2 2 1
3
2
1 11 1
ln 2 tan ,
2 2 1 1
A
(8)
2
1 2 2 2 2
2 3 1
2 2 1
1 13 1
ln tan ,
2 1 1
B
1
1
lnk p
.
THE INFLUENCE OF SURFACE ON SCATTERING OF CARRIERS IN n-PBTE 281
Experimentally obtained the thickness-dependent mobility () can
be explained by the mechanisms of carrier scattering on the surface
of the condensate. The mobility of carriers in case of diffuse scat-
tering on the surface is defined as follows [9]:
1
(1 )
b
k ; (8)
here, b—the mobility of carriers in the bulk material.
According to works of E. Justi [10] and H. Mayer [11], thermos-
e.m.f. S of films with a thickness dl is given as follows:
3
1 (1 )
8 1
b
l U
S S p
d U
. (9)
For thin films with a thickness dl,
ln 1.42
1
1
ln 0.42
b
l
U d
S S
lU
d
, p 0, (10)
where Sb—Seebeck coefficient for bulk samples, and parameter
( ln ( ) / ln )
E
U l E E
characterizes the energy-dependent l, E—
energy of electron, —Fermi energy. In the quadratic dispersion
law, U2 is predicted by the Bloch’s free-electron hypothesis.
4. THE RESULTS AND DISCUSSION
Theoretical dependence and experimental data for conductivity ,
Hall coefficient RH, mobility , Seebeck coefficient Sx on the thick-
ness of films based on n-PbTe are shown in Figs. 1–8. For the mas-
sive-sample parameters, experimental data for sufficiently thick
films, which are well consistent with data for bulk samples [12],
were used:
for the film on mica substrates: b150 Ohm
1cm
1, RHb–0.75
cm3/C, b158 cm2/Vs, Sb120 V/K;
for the film on sitall substrates: b9 Ohm
1cm
1, RHb–3.5 cm3/C,
b27 cm2/Vs, Sb93 V/K.
Figures 1 and 2 show the dependence of conductivity on the
film thickness of n-PbTe on mica substrates and experimental data.
As seen, with increasing film thickness d, conductivity increases
greatly with reached saturation at d300 nm for samples on mica
substrates and at d600 nm for samples on sitall ones. In this case,
dimensional effects have a significant impact, which is vanishing
with increasing thickness. The theoretical curve was calculated us-
282 M. A. RUVINSKII, O. B. KOSTYUK, B. S. DZUNDZA, and V. I. MAKOVYSHYN
ing the formula (3), and parameter p, and l was found. Best matches
of theoretical curve and experimental data were obtained by the
least squares method with special features in the Maple 18. The cal-
culated values for the reflectivity coefficient were as follow: p0.4,
q0.37 for the films on mica, and p0.08, q0.03 for the films
on sitall. Note that the values of coefficients of specular scattering
are comparable for both surfaces of film (Table 1).
Regarding the impact of the type of substrate, for the films ob-
tained on fresh chips of mica, specular–diffuse scattering mecha-
nism of carriers is realized, and for the films on sitall, scattering
mechanism of carriers closes to diffuse one completely (p0). This
is due to higher structural perfection of films on mica unlike films
on sitall.
Fig. 1. Thickness dependence of conductivity of the n-PbTe films on
fresh chips of (1000) mica-muscovite. Points—experiment, solid line—
calculation models according to Fuchs–Sondheimer theory.
Fig. 2. Thickness dependence of conductivity of the n-PbTe films on
sitall. Points—experiment, solid line—calculation models according to
Fuchs–Sondheimer theory.
THE INFLUENCE OF SURFACE ON SCATTERING OF CARRIERS IN n-PBTE 283
The dependence of Hall coefficient on the thickness was calculat-
ed according to Eq. (6) (Fig. 3; Fig. 4, curve 1). For films on mica
(Fig. 3), calculation for Eq. (6) satisfactorily describe experimental
data, and for the films on sitall, Eq. (6) only describes the range of
thin films, as noted by Sondheimer in Ref. [5]. Therefore, to de-
scribe the dependence of the Hall coefficient on the thickness, nu-
merical score with (7) proposed by Tellier et al. [9] was applied (Fig.
TABLE 1. The calculated values of parameter for the specular scattering
of carriers.
Type of substrate l, nm p q U
mica 265 0.4 0.37 0.60
sitall 548 0.08 0.03 0.62
Fig. 3. Thickness dependence of Hall coefficient RH of the n-PbTe films on
fresh chips of (1000) mica. Points—experiment, solid line—calculation
models according to Fuchs–Sondheimer theory.
Fig. 4. Thickness dependence of Hall coefficient RH of the n-PbTe films on
sitall. Points—experiment, solid lines—calculation models according to
Fuchs–Sondheimer theory.
284 M. A. RUVINSKII, O. B. KOSTYUK, B. S. DZUNDZA, and V. I. MAKOVYSHYN
4, curve 2).
The Larmor radius was calculated by the method of the least
squares D4.2510
7 m. This result coincides well with the calcula-
tion by the first approximation with the formula Dmv/(eB),
where m—mass of carrier, e—module of charge, B—magnetic field,
v—velocity of carrier. For these films, D4.5910
7 m.
Figures 6 and 7 present the dependence of Seebeck coefficient S
on the thickness of the n-PbTe film under the proposed model for
substrates from mica-muscovite and sitall. For the films on mica,
solid curve in Fig. 7 is calculated according to Eq. (9). For these
samples, the theory for the thick films well coincides with experi-
ment. The value of U0.6 was obtained by the least-squares meth-
od. It indicates a deviation from a quadratic dispersion law (U2
for quadratic dispersion law).
Various researches give different values of U. Huebner [13] ob-
Fig. 5. Thickness dependence of Hall mobility of the n-PbTe films on
fresh chips of (1000) mica. Points—experiment, solid line—calculation
models according to Fuchs–Sondheimer theory.
Fig. 6. Thickness dependence of Hall mobility of the n-PbTe films on
sitall. Points—experiment, solid line—calculation models according to
Fuchs–Sondheimer theory.
THE INFLUENCE OF SURFACE ON SCATTERING OF CARRIERS IN n-PBTE 285
tained U0.530.19 for the thin gold film at the temperature
between 77 K and 296 K. Chopra et al. [14] obtained U18.7 for
the thin copper films at T483 K. Thornburg and Wayman [15]
obtained U2.2 for the thin Au–Ni films.
For the films on sitall, similar behaviour was observed. The laws
for the thick films described the experimental data. The value
U0.62 was obtained by the least-squares method for the mica
substrates.
It is also worth noting that the examined samples have relatively
high Seebeck coefficient S200 V/K. However, higher values of
conductivity for the films on mica give greater thermoelectric
figure of merit for the films on mica, S24 W/K2cm, compared
with films on sitall, S20.4 W/K2cm.
An important parameter that affects to the value of the scatter-
ing coefficient is surface roughness, z. Ziman [16] proposed a mod-
el, in which, by analogy with optics, there is possibility of obtaining
mathematically exact expression for the scattering coefficient p.
Fig. 7. Thickness dependence of Seebeck coefficient S of the n-PbTe films
on fresh chips of (1000) mica. Points—experiment, solid line—calculation
models according to Mayer theory.
Fig. 8. Thickness dependence of Seebeck coefficient S of the n-PbTe films
on sitall. Points—experiment, solid line—calculation models according to
Mayer theory.
286 M. A. RUVINSKII, O. B. KOSTYUK, B. S. DZUNDZA, and V. I. MAKOVYSHYN
Then, according to [16], p is defined as
3 2 2
exp 16p z l , (11)
where z—standard deviation for the height from the reference plane
(surface roughness), l—mean free path.
1a 1b
2a 2b
Fig. 9. 3D AFM image of the surface of thin PbTe films deposited on chips
(0001) mica-muscovite (1) and ceramics (2) with thickness, d, nm: 270 (1b
and 2b), 810 (1a), 1350 (2a).
TABLE 2. Dependence of the scattering coefficient on the surface rough-
ness.
mica sitall
N
o
.
o
f
s
a
m
p
le
T
h
ic
k
n
e
s
s
d
,
n
m
T
h
e
m
e
a
n
s
q
u
a
r
e
r
o
u
g
h
n
e
s
s
z
,
n
m
T
h
e
s
c
a
tt
e
r
in
g
c
o
e
ff
ic
ie
n
t,
p
N
o
.
o
f
s
a
m
p
le
T
h
ic
k
n
e
s
s
d
,
n
m
T
h
e
m
e
a
n
s
q
u
a
r
e
r
o
u
g
h
n
e
s
s
z
,
n
m
T
h
e
s
c
a
tt
e
r
in
g
c
o
e
ff
ic
ie
n
t,
p
1a 810 10.62 0.45 2a 1350 35.67 0.12
1a2 540 6.73 0.73 2b 270 6.77 0.93
1b 270 5.02 0.84
THE INFLUENCE OF SURFACE ON SCATTERING OF CARRIERS IN n-PBTE 287
Figure 9 presents AFM images of a surface of studied films based
on PbTe. We see that the surface of film consists of nanosize crys-
tallites of pyramidal shape. It is established that the average size of
the nanocrystals increased with the thickness of condensate and the
surface roughness increased (Fig. 9). The substrate of film does not
significantly affect to the form of nanocrystals. However, the size
of crystallites for the films on sitall is larger than for the films on
mica. Accordingly, the surface roughness for the films on a mica
substrate is less than for the films on a sitall substrate (Fig. 9, Ta-
ble 2).
The calculated values of the scattering coefficient depending on
the roughness are shown in Table 2. As seen, for the coefficient p, a
clear dependence on the thickness of condensate for studied samples
is traced: it increases with the decreasing film thickness. For the
thin films, p is close to one that is indicating the mirror mechanism
of carrier scattering from the surface of film. In other words, mi-
nor irregularities of surface, which are compared to the mean free
path l, are not strongly impact on the characteristics of carriers’
flow. It should be noted that the formula (11) is a fairly approxima-
tion, and description of the surface with only one parameter z2 is
rather simplistic. For the thick films, the scattering coefficient p is
smaller and quite close to the values calculated within the Fuchs–
Sondheimer model (Tables 1, 2).
5. CONCLUSIONS
1. The analysis on theoretical calculation of electrical parameters of
films based on the Fuchs–Sondheimer and Mayer models.
2. The electrical parameters of n-PbTe films on substrates of mica
and sitall are experimentally studied. The influence of mechanism
of surface reflection of electrons on the thickness dependence of
conductivity, Hall coefficient, and thermo-e.m.f. is determined.
3. The probability of specular scattering of charge carriers on both
the free surface of film and the film–substrate boundary is deter-
mined. As shown, for the films on sitall substrates, completely dif-
fuse scattering of carriers (p0) is implemented, and for the films
obtained on fresh chips of mica, the scattering coefficient p0.4.
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