SCIENTIFIC ABSTRACT VAVILOV, V.S. - VAVILOV, V.S.

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• Publication Date: December 31, 1967
• Content Type: SCIENTIFIC ABSTRACT


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SUBJECT USSR / PHYSICS CARD 1 PA - 1251
AUTHOR VAVILOVt V.S.
TITLE San-P-M-E-s. _(Yn the Direct Transformation of Ra(liation Energy
into Electric Energy with the Help of Photoelements),
PERIODICAL Atomaja Energija, L, fasc. 3, 107-116 (1956)
Publ. 3 / 1956 reviewed 9 / 1956
Semiconductor thermopiles are mentioned which were suggested by the acad-
emician A.I.IOFFE and were successfully developed in the USSR without, how-
ever, being discussed on this occasion. Semiconductor photoelements with
barrier layer have been known since the valve photoelements have been in-
vented by W.A.ULIANIN (Wied.Ann. JA, 241 (1888), but until recently the
efficiency of these photoelements has never been more than some tenths of
a %. By investigating the main properties of semiconductors, like those of
the mechanism of electrons and the hole conductivity, the life of current
carriers in semiconductor crystals, and the rectification of the current at
the contacts between jemiconductors, it was possible to predict the proper-
ties of photoelements from Ge and Si and to attain efficiencies in practice
of up to 11%. Thus it i~ now possible to obtain more than 100 watt of
electric energy per 1 m of a surface directly irradiated by the sun.
Some properties of semiconductors used in sun piles: The basis of the
element of the sun pile is a semiconductor crystal which contains two domains
separated by a sharp boundary and having different mechanisms of electric.
conductivity. This boundary is called - not quite correctly - "electron-

At.omaja Energija, L, fasc. 3, 107-116 (1956) CARD 2 / 6 FA - 1251
hole-transition". Like their "relative", the diamond, pure Germanium and
silicon without admixtures or structural blemishes act as insulators at
room temperature and at low temperatures. By the addition of extremely small
quantities (10-5~) of atoms of the III. and V. group of the periodic system,
it is possible to control the mechanism of electric conductivity and the
specific resistance in the various domains of the crystal.
If a silicon crystal in one of its nodes contains an arsenic atom with 5
valen,;e electrons, then 4 of them are occupied by the "bindings" keeping the
atom in the node, but one of them remains free and wanders about in the
crys';a1.
If admixtures with 3 valence electrons are used, Si- or Ge-crystals are ob-
tained in which the electric current is transmitted as by positive charges.
("Hole conductivity"). This conception of holes is well suited for the de-
scription of the drive- and diffusion processes.
The semiconductors of sun piles are unbalanced by the absorption of solar
radiation, on which occasion an excess of holes or electrons will be found
to exist. Photons with more than 1,12 eV (i.e. with a wave length that is
shorter than 1,1 micron), give up their energies to the silicon crystal and
thereby liberate bound valance electrons. These electrons diffuse in the
crystal until recombination occurs. The average "diffusion length" covered
to L rJ_k7T,' Sufficiently great
by the electrons or holes amounts

Atomaja Energija, 1, fasc. 3, 107-116 (1956) CIRD 3 / 6 P,~ - 1251
diffusion lengths (several mm) are found only in very perfect monocrystals of
3emiconductors.
Next, the electron-hole-contacts (transitions) between the domains which are
enriched with donors and acceptors are described. On the occasion of the arti-
ficial production of crystals with electron-hole-transition it is not
necessary to do away with the admixture of one of the conductor types in order,
by adding the other admixture, to obtain the necessary conductivity for the
corresponding part of the crystal, for it is quite sufficient to introduce
the admixture necessary for the neutralization of the admixture of the other
type plus a certain surplus. To one donor or acceptor there correspond
107 to 108 atoms of the basic material.
The main property of electron-hole-transitions is the capacity of rectifying
the electric current. This property is based on the existence of a domain
with space charge which forms a potential step for the electrons and holes.
Here a qualitative explanation for the phenomena occurring on the occasion of
the rectification of the current by a semiconductor crystal with electron-
hole-transition is given. The number of liberated "holes" and therefore also
the inverse current declines with declining temperature and with an increase of
the energy E which is necessary for the liberation of an electron bound with-
in the systeg of "valence binding". This energy amounts to 0,75 eV for Ge and to
-1,12 V for Si.

Atomaja Energija, 1, fasc. 3, 107-116 (1956) CARD 4 / 6 PA - 1251
Sun piles - silicon photoelements with electron-hole-transitions. By the
absorption of photons and production of electron-hole-couples solar energy
is transformed direct into electric energy, i.e. into the energy of the
electrons in the crystal. However, without electron-hole-tranBitions only
the concentration of these charge carriers in the semiconductor (i.e.
photoconductivity) would increase near this absorption. On the basis of a
diagram the phenomena taking place in a semiconductor near the electron-
hole-transition are discussed. Apparently the electrons and the holes are
"separated" by the potential barrier of the electron-hole-transition, i.e.
there is free transition of electrons into the domain of electronic conduc-
tivity, which is thus charged negatively, while the holes wander into the
hole-domain which they charge positively. In consequency of the concentra-
tion of the charge carriers the potential barrier V k diminishes. If the
outer circuit is open, a dynamical equilibrium of the primary diffusion
current of the surplus current carriers and of the inverse current which is
caused by the accumulation of the space charge of the holes in the P-domain
and of the electrons in the N-domain, is established, If the outer circuit
is short-circuited the entire diffusion current passes through and in the
case between these two extremes the current is distributed over the outer
circuit and over the interior of the crystal.
Next, the equivalence scheme of the sun pile is discussed on the basis of
a drawing and computed. The diffusion current I D is equal to the short

Atomaja Energija, I., fasc. 3, 107-116 (1956) CARD 5 / 6 PA - 1251
circuit current, and the latter is forked in that one part, na=ely I, enters
the load circuit with the load R, and the other, namely I n, is caused by the
inverse passing through of the carriers. The corresponding part of liberated
energy is lost. For the maximum potential difference it applies that
Vo - (kT/q)ln((qI R /kT) + 1). Here the null resistance R i-Lonnected with
D 0 0 r
tho saturation current of the electron-hole-transition as follows: 1 0 -kT/qR0
(q denotes the charge of an electron).
Electron-hole-transitions are in considerably more intense in silicon than in
germanium. This difference is due above all to the greater width of the for-
bidden zone of Si (1,12 ev) in comparison with Ge (0,75 3V). The theoretical
efficiency of Si-photocells may, in the case of a direct incidence of solar
radiation and at 250 C, attain 18%. Slight cooling down (as e.g. to 00 C) in-
creases the degree of efficiency.
Such "sun piles" were constructed in 1954-19551 they consist of large silicon
monocrystals (4-5 cm per element). The electron-hole-transitions of these
crystals are located rather close to and under the surface to be irradiated.
The production of sufficiently large Si-monocrystals is still very difficult.
A further technical difficulty is presented by the problem of mounting the
electrode which is transparent for visible and infrared light on the surface
of the crystal. This and the establishment of the electron-hole-transition in
the desired depth was brought about by the thermal diffusion of the admixture

Atomaja Energija, L, faac. 3, 107-116 (1956) CARD 6 / 6 PA - 12511
electrons. According to D.CHAYIN et al. J.Appl.Phys. 25, 676 (1954) the best
results are obtained by the diffusion of boron (as acceptor) in N-silicon at
a temperature that is near the melting point of Si (14000 C). Different
varieties and details of this procedure are described.
In the silicon photoelements the maximum of the transformation is about
A - 0,75,w , on the boundary Of the red and infrared spectral domains. To
this wavelength there corresponds nearly exactly the maximum number of photons
in the spectrum of solar radiation. Thusq a silicon photoelement with electron-
hole-transition near the surface causee a nearly perfect transformation of so-
lar energy. Because of the relatively good transmissivity of clouds and fog
for infrared light, sun-piles operate also in dull weather, although, of course,
their efficiency will be somewhat lower.
The dependence of theelectromotoric force and of the short-circuit current of a
silicon photoelement on light conditions as well as the load characteristic of
such photoelements are shown in a diagram. The load characteristics have their
maxima at ~ 093 V in the case of an illumination of 1 milliwatt per cm2 and
less. Therefore, receivers necessitating a constant voltage at the input (e.g.
accumulators) may be used in connection with sun piles within a wide range of
illumination strength. - Within the coming years simple and sufficiently inex-
pensive methods for the production of semiconductor photoelements with large
surface and high degree of efficiency will probably be worked out, so that the
direct transformation of solar energy will be able to occupy the place it de-
serves within the framework of "low power economy".
INSTITUTION:

U~ta/Electricity Semiconductors G-3
As Jour : Referat Zhur - Fizika, No 5, 1957, 12183
Author : Vavilov, V.S., Smirnov, L.S., Galkin, G.N., Spitsyn, A.V.,
ViitA_ev_icH_,_V.M.
Inst : Physics Institute, Academy of Sciences, USSR, Moscow.
Title : Formation of Defects of CT-jstalline Lattice in Germanium
Upon Bombardment by Fast Electrons.
Orig Pub : Zh. tekhn- fiziki, 1956, 26, no 9, 1865-1869
Abstract : Thin (50 microns) platelets of single-crystal n-germanium
with bombardment of monoenergetic electrons with energies
from 400 to 1000 kev. The concentration of the lattice
defects arising thereby was calculated from the variation
in the specific resistivity ~ of the specimens before
and after the irradiation. The threshold value of the
energy starting with which increases upon
Wmin'
Card 1/2

"The Structural Defects in Germanium Monocrystals Irradiated by Beta-
Particles and Fa~.'t Neutrons and the Influence of These Defects on --aectron-
Hole Recombination," V.S. VAvilov, L.S. Smirnov, A.V. Spit.Tjn, V.M.
Patskevich. M.V. Chukichev, Moscow, USSR
Paper submitted for presentation at the International Conference on
Radioisotopes in Scientific Research, Paris 9-20 Sep 1957.
USSR Acad. of Sciences, 140scov

AUTHORS: Galkin, G.N. and Vavilov, V.S. 120-4-14/35
TITLE: Measurement of the Zifetime of-Mlarge Carriers and their
Drift Mlobility in Silicon. (Izinereniye vremeni zhizni
nositeley zaryada i ikh dreyfovoy podvizhnosti v kremnii)
PBRIODICAL: Pribor,.r i Tek1hnika Eksperimenta, 1957, No.4,
Pp. 52 - 56 (USSR)
ABSTRACT: Apparatus is described by which the lifetime and mobility
of electrons and holes in mono-crystallic silicon can be
measured. The pulse method is used and traps are filled by
illumination of the crystal. The apparatus can be used for
measur,:~ment of lifetimes from 1 psec.
The method is based on the drift under the action of an
applied eleetz�c field, of in_�nority carriers introduced into
the semi-conductor by a point contact (emitter) to which is
applied s short pulse (0.3 ~lsec)- After a time lag, a rect-
angular pulsed electric field is applied to the specimen.
The introduced non-base carriers move along the specimen and
on passing the collector, create an opposition pulse
(collector response) irhich is displayed on an oscillograph.
The block diagram is ,7,~iven in FiC.1 and the oscillog-raph
display in FiC;. 2. By chanGinG the time lag, a different
Cardl/4 height of the collecto~r response H can be obtained,

120-4-14/35
Measurement of the Lifetine of Mia_-~~e Carriers and their Drift
Mobility in Silicon.
depending on the maximum concentration of te non-base
carriers at the instant they pass near the collector. For
a short emitter pulse and with small deviation from equi-
librium concentration, H is given by:
H --1- (1/47) exp (- t/-r
The first factor corresponds to diffusion and the second
to recombination. Here, -c is the lifetime of the minority
carriers. Log (HV-T) is plotted against t giving a
straight line with a slope equal to -1/'t. The presence of
traps can be detected by the shape of the collector response
(Fig-3). The specimen is illuminated until asymmetry of the
collector response is eliminated.
The injection level can also be Judged by the shape oIL the
collector response, since a large quantity of minority
carriers chanEes the conductivity of the material and causes
asymmetrical distortion of the pulse (Fig.4). Thus the
method indicates w1hen the traps are filled and when the
concentration of the minority carriers is sufficiently low.
Card2/4 To avoid non-linearity of the collector, contact with small

120-4-14/35
Measurement of the Lifetime of Charge Carriers and their Drift
Mobility in Silicon.
concentrations of the non-base carriers near the collector$
the intensity is increased by illumination of the surface near
the collector by white liGht (Granville and Gibs(.,n method,
Re-'L ?and 13).
The mobility u d was determined by the formula:
ud = L/ t - ";
where L ic the distance between the emitter and the collector,
t is the time between the applic.-ition of the ptilse and the
reception of the response, E is the applied field.
The time t is found by extrapolation of the graph of H
against t to H= 0 (Fi,-.7). L is measured by a measuring
falcroscope, nnd E is fotind by backinC. off an oscillograph
displaying the voltage.
The table shows that for measurements ^C > 3 4sec. , the error
does not exceed 10%j, and down to 0.2 jisec. 1007o. The errors of
ud do not exceed 101;0" and co.,11pare viell with valijes given in
the literature. There are 9 figures and 13 references, 5 of
Card3/4which are Slavic.

120-4-14/35
Measurement of the Li-ttime of Charge Carriers and their Drift
Mobility in Silicon.
. ASSOCIATION: Physics Institute imeni P.N. Lebedev Ac.Sc. USSR.
(Fizicheskiy ihstitut im. P.N. Lebedeva A111 SSSR)
SUBMITTED: March 2, 1957.
AVAILABLE: Library of ConEress
Card 4/4

Rr,
,ergy of Ionization bY 3eta-Particles In Crystals of 3--rmanjugn arAl
V.S. Vavilov, L.S. Smirnov, V.M' Patskevich, Moscow, USSR.
Paper submitted for praz~entatlon at the International Conference on
Radioisotopes in Scientific Research, Paris, 9-20 Sep 195~'-
Acad. Sci. USSR, Moscow

7AVILOVLM V. S.
&u*WWFWW--' Ps=
.%.miconductor converters of radiation energ7. Doo. ouch. fiz.
no.53209-226 157. (MIRA 1636)
(Transistors)

US8R/Electricity 8emiconductors G-3
Abs Jour : Ref Zhur - Fizika, No 1, 1958, 1303
Author : Vul, B.M., Vavilov, V.S. Smirnov, L.S., Gelkin, G.H.,
Patskevich,li~~.W._" A.V.
Inst
Title Transformation of the Energy of /3 Particles Into Electric
Energy in Germanium Crystals with P-N Junctions.
Orig Pub Atomn. energiya, 1957, 2, No 6, 533-536
Abstract The authors report results of an investigation of the di-
rect transformation of the energy of /,' particles into
electric energy in germanium crystals of the n-type with
p-n Junctions, obtained by melting-in indium. The sour-
ces of the /Z particles were the compounds Sr90 - Y90
with activities of 50, 100, and 200 millicurie. The ex-
periments were also performed with artifici&Uy-accelera-
ted electrons with energies from 400 to 1150 kev, the in-
tensity of the electron beam reaching values corresponding
Card 1/3

I
USSR/Electricity - Semiconductors G-3
Abs Jour : Ref Zhur - Fizika, No 1, 1958, 1303
a secondary role. It is indicated that it is possible to
restore the initial properties of crystals by heating
them. Orther possible types of semiconducting energy trans-
formations to transform the energy of radioactive decay
into electric energy are considered.
Card 3/3

PA - 2148
Probability of Charge Carriers by Frankel Defekts in
N-Germanium.
restitution of the original life. If the number of defects
.,ccouring in the chrystal lattice is compared with the
Attendant circumstance of reduction of life the capture
cross-section of the carriers (holes) can be estimated
(by the new-formed recombination-centers). The formula for
the capture or6sa-section is derived on the assumption that
the number of new recombination-centers is equal to the
number of Frankel-defects and that all these centers are
filled with electrons. Experimental result for this domain
which must be considered to be the lowest of the actual
value, were approximativelY 7*10-17cm2. (1 image).
ASSOCIATIONt Physical Institute "P.N.Lebedev", Moscow.
PRESENTED BY:
SUBMITTED: 1.10-1956
AVAILLBLE: Library of Congress.
Card 2/2

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AUTHORS
TITLE
PERIODICAL
ABSTRACT
Patskeyich, V.M. , Vayiloyj V.S. 'Smirnov, L.S. 56-3-43/59
Electron lonizaiTo-n Energy in Silicon Crjstala. (Energiya ionizataii
elektronami v kristallakh kreumiya) (latter to the Editor)
Zhurnal Eksperim.i Teoret.Fiziki,1957,Vol 35,11r 3,pp 804-805(js~ii)
The "multiplication coefficient" 13 of the charge carriers was mea-
sured on a silicon monocrystal of the P-type with P-N-transitions.
Irradiation by electrons with an enbrgy of from lo to 3o keV took
place vertically to the N-type side of the crystal,but parallel to
the P-N-transitions.From the coefficient 8 measured the quantity 6
was determined as ij,2 + 0,6 eV.
There are 2 figures and 5 Slavic references.

AUTHOR
TITLE
PEhIODICAL
ABSTRACT
Card 1/4
53-1a-8/18
VAVIIDV, V.S., MAIDVETSY4YA, V.-IL., GALKIN, G.N., WMSWlp A.P.
STITcon SoIrr Batteries as Sources of the Blectric Feeding of Art1ficial.
Earth Satellit-3
'Kranniyevyye soinedzWe batarei kak istochniki elektricheakogo pitaniya
iskusstvennykh sputniRov zemli. Russian).
Uspekhi Fiz. Nauk,, 1957, Vol 63, Nr la, pp 123 129 (U.S.S.R.)
For artificial earth satellites it is of advantage to use solar batte-
ries in connection with buffer accumulators because they are effective
during the whole time of flight of the satellite (outside of the earth's
shadow).
The principle of the effect of a semiconductor transformer with P-11-
-transitions, in the course of this process the energy of solar -ragla-
tion is Ur-Es-formed into electric energy as follows: A photon is ab-
sorbed and an'lelectron-hole" pair is produced. In the case of lacking
P-11-transition, however,, the concentration of the electrons and holes
in the semiconductor would increase in the vicinity of the absorption
domain of light. The authors here investigated the diagram. of the ener-
gy states of the electrons and holes in the secLiconductor in the vici-
nity of the artificial produced P-N-transition. This diagram then supp-
lies information concerning the mode of operation of the photoelement.
Within the domain of the P-11-transition there exists a potential barrier,

Silicon Solar Batteries as Sources'of the Electric Feeding-of Artificial
Earth Satellites
the height V k of which can be nearly'as great as the width E 9 of the
forbidden zone (in the case of silicoln 111 e~,). The electrons and holes
produced on the occasion of the absorption or light diffuse to P-H,
-transitf;n: The potential barrier 'of the P-N-transition then probably
"separates" the electrons and holes so that the electrons advance free-
ly to the domain of the electronic (N)-conduction of the crystal to
which they then give a negative charge, On the occasion of tranlition
into the domain of the hole-conditioned conduction line the holAs charge
the crystal positively. As a result of the change of the concentrations
of the charge carrier the height of the potential barrier decreases. A
diagram shows the dependence of the effective coefficient of a perfect
semiconductor transfortner with P-M-transition upon the width of the for-
bidden zone. The effective coefficient at first increases considerably,,
attains its maximum value at a width of 1,3 eV, and then gradually de-
creases again. In none of the known cases was the ifeal effective use-
ful coefficient of about 22 0/0 attained. The auth4rs developed a me-
thod for obtaining P-N-transitions in monocrystals of P-silicon by the
Card 2/4 thermal diffusion of phosphorus from the gaseous phase. Various'details

53-la-8/18
Silicon Solar Batteries as Sources of the Liectric Feeding of Artificial
Earth Satellites
of this method are discussed. The construction of an experimental sili-
con photoelement is shown in anillustration.
The Volt Nre characteristics and the charge characteristics:
The vol ampkAre characteristic of a photoelement with a su-r-ra-ce of
Os95 cmO irradiated by sunlight is shown in a diagram. For the darkness
volt-amore characteristic in the domain of the direct current a formula
is written down. The optimum load resistance R can be determined from
the load characteristic as well as by computat%n. Thb authors here
point to the following means of further increas#g the effective coeffi-
cient of transformationo,
1,) Increase of the effective useful coefficient a to one,
2.) Decrease of the resistance '