The dependences of electric and photoelectric parameters of the heterojunctions p-Si/Cd<sub>0.3</sub>Zn<sub>0.7</sub>S<sub>0.4</sub>Se<sub>0.6</sub> on the thermal
annealing regime are investigated. It is shown, that after thermal annealing at 400°C for τ = 6 min, a recombination rate on the
interface does not almost change in a wide range of temperature.
As the annealing temperature was increased from 0 to 170°C (τ= 2min), the intensity of peak in the λml = 0.593 μm
wavelength region sharply increases. Upon heart treatment in air at <i>t</i> = 400°C for 5 ÷ 6 min, heterojunctions exhibit high
photosensitivity over a wide spectral range (0.560 - 1 .38 μm). The evaluation of solar cell parameters was carried out using the
dark and light current-voltage characteristics. The open circuit photovoltage and short circuit photocurrent density of HJ were
V<sub>oc</sub> = 0.564 V, <i>J</i><sub>sc</sub>= 1 8.7 mA/cm<sup>2</sup>, respectively.
Effective thin film heterojunctions SnO<sub>2</sub>/Cd<sub>0.8</sub>Zn<sub>0.2</sub>S<sub>0.1</sub>Se<sub>0.9</sub>/p-CdTe/Cu were manufactured by the method of
electrochemical deposition. It is shown, that not treated heterojunctions possess the sensitivity only in visible region of
spectrum. At illumination by the solar simulator with W = 100 mVt/sm<sup>2</sup>, not treated structures had the following
photoelectric parameters: I<sub>sc</sub> ≈ 4.76 mA/cm<sup>2</sup>, 0.448 V, D* = 3 x 10<sup>4</sup> cm x Hz<sup>1/2</sup>Vt<sup>-1</sup>. Annealing of samples in air results to
substantial increase of photosensitivity is found. After TA at <i>t</i> = 350°C and τ = 9 min, the sensitivity of samples in the
0.8 - 1.0 μm wavelength region sharply increase, that is due to formation of films Cu<sub>2</sub>Se at thermal annealing by means of
diffusion of copper atoms from buffer contact through CdTe to Cd<sub>0.8</sub>Zn<sub>0.2</sub>S<sub>0.1</sub>Se<sub>0.9</sub>. Thus investigated structures possess
following values of short circuit photocurrent, open circuit photovoltage and detectability: 1<sub>sc</sub> = 19,4 mA/cm<sup>2</sup>,
U<sub>oc</sub> = 637 mV, D* = 8 x 10<sup>6</sup> cm x Hz<sup>1/2</sup> x Vt<sup>-1</sup>.
p-Si/n-Cd<sub>1-x</sub>Zn<sub>x</sub>S heterojunction are prepared by the electrodeposition method. Electrical and photoelectrical measurements have been carried out on heterojunctions having varying Cd<sub>1-x</sub>Zn<sub>x</sub>S films composition 0 ≤ x ≤ 0.8 heart treatment temperature and time. It was found that annealing the heterojunctions at T<sub>a</sub>=350 ÷ 380°C for τ<sub>a</sub>=5÷8 min in air leads to an increase of photosensitivity in the 0.8÷1.34 μm spectral region. The detectivity, open circuit photovoltage and short circuit photocurrent density for heterojunctions p-Si/Cd<sub>0.3</sub>Zn<sub>0.7</sub>S were D*=(5÷8)•10<sup>6</sup>cm•Hs<sup>1/2</sup>•W<sup>-1</sup>, V<sub>oc</sub>=0.6 V <sub>H</sub> I<sub>sc</sub>=5.6 mA/cm<sup>2</sup>, respectively.
The processes of photochemical reorganization of deep levels of the photoactive centers in films CdS<sub>1-x</sub>Se<sub>x</sub> (0 ≤ x ≤ 0.8) prepared onto molybdenum substrates by the method of electrochemical deposition were investigated. It is established that thermal annealing of investigated films in air at T<sub>a</sub>=380 ÷400°C for τ<sub>a</sub>=7÷8 min leads to occurrence of new longwavelength maximum in the photosensitivity spectrum at λ=0.95-1.15 μm (depending on the selenium content) which is due to oxygen-containing photoactive centers forming at disintegration of (V<sub>Cd</sub>-Cd<sub>i</sub>)<sup>+</sup> pairs. The mechanism of formation and disintegration of donor-acceptor pairs have been proposed and basic parameters of complex centers formed at thermal annealing were determined by the method of photocapacitance and photoconductivity spectroscopy.
In the present work the features of an impurity and induced impurity photoconductivities in IR region, and also anomalous photoconduction and photochemical reaction in Cd<sub>1-x</sub>Zn<sub>x</sub>Se films are considered depending on film deposition and heat treatment (HT) modes. The formation of Cd<sub>i</sub>-Cd<sub>i</sub>, Zn<sub>i</sub>-Zn<sub>i</sub>, V<sub>se</sub>-Zn<sub>i</sub> etc. associations in Cd<sub>1-x</sub>Zn<sub>x</sub>Se films, providing occurrence of optical active electronic states, carried in an interval of energy 0.3÷0.6 eV, allows to use of these films for creation non-cooled photodetectors of IR-range. At illumination of films by λ=0.95 μm light, the anomalous photoconductivity and photomemory phenomenon were observed, connected with defects of metastable states, which concentration can be controlled by film structure, deposition and HT modes, and limits by tunnel transitions of no basic located electrons and holes between <i>r</i>- and <i>s</i>-centres. The photochemical reaction with activation energy of 0.17÷0.21 eV, was observed at illumination (by λ=1.25 μm light) of Cd<sub>0.8</sub>Zn<sub>0.2</sub>Se films heart treated on air during 10÷15 minutes. It represents a disintegration process of donor-acceptor pairs, consisting r-centres and Cd<sub>i</sub>, Zn<sub>i</sub> donors, and caused by precipitation conditions and HT.
The negative infrared photoconductivity (NPH) has been observed for the first time in CdS<sub>1-x</sub>Se<sub>x</sub> films, in the wavelength region of 0.700 ÷ 1.23 μm. at values of stimulating light intensity Φ = 100 ÷ 400 Lk. electrical field E = 0.5 ÷ 130 V/cm and temperature T = 265 ÷ 310 Κ. It is established, that basic laws of NPH explains on the basis of two-barrier model and in the considered conditions a charge carriers, overcome a barrier by tunneling. A films of CdS<sub>1-x</sub>Se<sub>x</sub> can be used in IR engineering and negatronics.
The Cd<sub>1-x</sub>Zn<SUB>x</SUB>Se films, deposited from solution, differ by high photosensitivity in visible and near IR region of spectrum. In present paper are called the results of induced impurity photoconductivity (IIP) of Ccd<sub>1-x</sub>AN<SUB>x</SUB>Se (0 less than or equal to x less than or equal to 0.5) films in region of 2.5-3.0micrometers . The Cd<sub>1-x</sub>Zn<SUB>x</SUB>Se films are obtained on glass-ceramic substrates by chemical deposition from aqueous solution, containing cadmium and zinc salts, and thiourea. The films are subjected to heat-treatment in air at temperatures 400-500 degree(s)C for 0-30 min. A quasi-linear spectrum of IIR adjoins to band according to impurity band from the side of high energy. At the spectrum of IIP have been observed narrow bands, the half-wide is 0.03-0.04 eV. With increasing the levels of primary photoexcitation the deformation of IIP spectrum to region of high energy, which appears in bands spectrum maximum. The value of violet shear is equal to (Delta) E=0.05 eV. The values of these phenomena are determined by nature of multi- levels associate, which are related to the optical activated sticking centers of electrons. At the same time the intensity of wide IIP band (hv<SUB>o</SUB>=0.3eV, in a low- temperature region) weak dependancies on temperature, on which testily band-impurity character of ionization of according ionizated donor centers. The isolated donors characterized by level of E<SUB>c</SUB>=0.29-0.32 eV and cross- section of capture (S<SUB>n</SUB>=(2-4)x10<SUP>17</SUP> m<SUP>2</SUP>). Their participation in called associated provides appearance of systems of optical active electron states, entered in energy range of 0.3-0.6 eV, having conditioned by high-temperature stable photosensitivity of Cd<sub>1-x</sub>Zn<SUB>x</SUB>Se films in IR-region. It is shown that, the studied Cd<sub>1-x</sub>Zn<SUB>x</SUB>Se films could be in use as an ordinary and cheap elements of memory of optical records, transformers of visible light to infra-red (IR) radiation.
In this work the results on the investigation of the photosensitivity near the IR region, of CdS<SUB>1-x</SUB>Se<SUB>x</SUB> (0 less than or equal to x less than or equal to 0.4) films 8 divided by 9 micrometers thick prepared on glass-ceramic substrates by precipitation from aqueous solutions are presented. The temperature dependence of dark and light conductivity, spectrum and optical quenching of primary and impurity photoconductivity are investigated. The obtained results show that when controlling ionic composition and heat-treatment (HT) conditions, one can purposely control the properties of CdS<SUB>1-x</SUB>Se<SUB>x</SUB> (0 less than or equal to x less than or equal to 0.4) films, achieve the appropriate degree of compensation of different recombination levels and traps attributed to intrinsic defects or impurities, which result in high level of photoelectrical parameters near the IR region. Just after deposition the photoconductivity spectrum maximum of CdS<SUB>1-x</SUB>Se<SUB>x</SUB> (0 less than or equal to x less than or equal to 0.4) films is observed at (lambda)<SUB>1</SUB>=0.495 divided by 0.545 micrometers versus the film composition. Subsequent to HT, the photoconductivity spectrum considerably widens and appears the impurity maximums at (lambda)<SUB>2</SUB>=0.58 divided by 0.69 micrometers and (lambda)<SUB>3</SUB>=0.95 divided by 1.05 micrometers. At (lambda)=0.88 divided by 1.56 micrometers wavelength region, the primary photocurrent optical quenching (POQ) of the films takes place. The POQ spectrum in photosensitive CdS<SUB>1-x</SUB>Se<SUB>x</SUB> films consists band with the maximum at (lambda)<SUB>max</SUB>-1.28 divided by 1.38 micrometers, versus the film composition and HT conditions. At optimum conditions, the degree of quenching attains to 12%. The quenching of the primary photoconductivity by infrared light, leads to the occupation of the r-centers by holes.