Вивчено закономірності електрохімічного одержання гібридних наноструктур на
основі тонких шарів поліаніліну на поверхні поруватого кремнію в умовах електрохімічної полімеризації аніліну з циклічною розгорткою потенціалу. Методом атомносилової мікроскопії досліджено топологію поверхні отриманих структур. Виявлено,
що наявність тонкого поліанілінового шару спричиняє незначний зсув максимуму і
деяке послаблення фотолюмінесценції поруватого кремнію, а також окисновідновну та сенсорну активність одержаних наноструктур.
Ключові слова: поруватий кремній, електрополімеризація, поліанілін, наноструктура, фотолюмінесценція..
Belong the semiconductor materials a special place is occupied by the heterogeneous systems based on
nanoporous silicon (PS), having a wide application in optoelectronic and sensor devices. Of great interest are
the heterostructures created on the PS and surface organic layers, among which the conjugated conducting polymers
now intensively studied. In the present work the possibility of electrochemical obtaining of the hybrid
nanostructures based on thin polyaniline (PANI) layers on the surface of porous silicon in the conditions of
electrochemical polymerization has been investigated. The porous silicon layers were formed by etching of the
silicon wafers (100) with n-type of conductivity in a 40% HF ethyl alcohol solution at a current density of
10 mA.
cm-2 during 20 minutes. For creation of PS-PANI hybrid layer a method of electrochemical polymerization
with cyclic potential sweeping in 0.1M solutions of purified aniline in 0.5 M H2SO4 was used. A wafer of
PS of the area of 1 cm2 was as an operating electrode, a platinum wire was used as a counter electrode and
saturated Ag/AgCl electrode was employed as a reference. The potentiostat PI-50 was a power source. After
film coating the samples were rinsed with deionized water and dried under vacuum at 353 – 373 K. Linear
dependence of the peak current on the potential sweep number in the interval of N = 4…16 give the possibility
to control the process of electroactive film formation on the surface of the porous silicon. The surface topology
of the prepared structures was investigated by the method of atom force microscopy. It found that PANI films
obtained on the surface of PS by electropolymerization method in general repeat the relief of the surface
forming a continuous polymer layer. However, the morphology of the films is difficult interpret due to the
irregularity of PS surface. As has been shown by the profile analysis of PS-polymer heterostructure a thickness
of PS-polymer layer achieves 40–45 nm.
Obtained nanostructures were examined on the ability to photoluminescence (PL) and electrochemical
activity. Higher electrochemical activity of PS-PANI nanostructure in comparison with PS probably connected
with particularities of the polyaniline structure, obtained in the condition of electropolymerization with cyclic
potential sweeping where polymer synthesis proceeds both on the surface and inside the silicon pores. It has
been found that presence of the thin polyaniline layer causes an insignificant displacement of the maximum
and some weakness of PL in comparison with PL of clean porous silicon.
Because electrical and optical properties of PANI is significantly depend on the level of oxidation or
reduction, this polymer is very sensitive to the action of chemical substances (value of рН, adsorption of polar
gases), therefore coating of PS by PANI film may improving the properties of sensor devices based on PS. A
sensor activity of the obtained heterostructures in gas medium has been study. It found that increasing the
ammonia pressure leads to growing the PL intensity, which may be explained by the processes of PANI film
reduction with formation of colorless form of polymer - leucoemeraldine, in result of this increases an optical
transparence of the film and, correspondently, yield of emission.
Key words: porous silicon, electropolymerization, polyaniline, nanostructure, photoluminescence
Изучены закономерности электрохимического получения гибридных наноструктур на основе тонких слоев полианилина на поверхности пористого кремния в условиях электрохимической полимеризации анилина с циклической разверткой потенциала. Методом атомно-силовой микроскопии исследовано топологияю поверхности полученных структур. Установлено, что наличие тонкого полианилинового слоя вызывает незначительный сдвиг максимума и некоторое ослабление фотолюминесценции пористого кремния, а также окислительно - восстановительную и сенсорную активность полученных
гетероструктур.
Ключевые слова: пористый кремний, электрополимеризация, полианилин, наноструктура, фотолюминесценция.
