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Semiconductor Photoconvertors under Electron Beam Irradiation

#A-190.2


Effect of Electron Beam Irradiation on Characteristics of Semiconductor Photoconvertors Based on New Materials and Structures

Tech Area / Field

  • MAT-ELE/Organic and Electronics Materials/Materials

Status
3 Approved without Funding

Registration date
09.02.2001

Leading Institute
Yerevan Research Institute of Optical and Physical Measurements, Armenia, Yerevan

Collaborators

  • National Renewable Energy Laboratory, USA, CO, Golden\nUniversity of California / Department of Chemistry, USA, CA, Irvine

Project summary

The proposed work is aimed to research the opportunity for the increase in the efficiency of the large band gap oxide photoelectrodes at the expense of the extending its spectral photosensitivity region into the visible part of spectrum through varying the impurity – defect content of the sample, and in the case of photovoltaic converters (based on the narrow band gap Si with p-n-junction) creating size quantized states in the Si surface layer under electronic beam irradiation.

According to the analysis of the first year study results in the framework of the Project #A-190d (PDG) and in conformity with the ISTC Manager Board recommendations the studies in the next two years will be focused on research of the photoelectrochemical and photovoltaic converters which are perspective solar energy ones.

The above mentioned studies were shown, that the Project working hypothesis addressed to the improvement of the characteristics and increase in the efficiency of the photoelectrochemical and photovoltaic converters of the solar energy was justified itself. The obtained results are promising and interesting from both the practical point of view and the point of view of understanding the complex physical and physical-chemical processes taking place at the semiconductor-electrolyte interface and at the surface layers of silicon. In particular, the fluorination leads to narrowing of the wide band-gap semiconductor electrode band-gap and hence to the increase in efficiency (about 30%) of the solar energy converters.

The substantiation of the proposed conception of the increase in the efficiency of the photovoltaic converters is motivated if the size-quantization at the surface layers of silicon is available. The improvement in performance of the solar energy converters under electronic beam irradiation was experimentally revealed.

On the above-mentioned base the A-190 Project Work Plan for the next two years has been prepared according to the ISTC Governing Board and coordinated by the collaborators.

A new collaborator, D. Sc., Scott Ward, from the National laboratory of renewable energy in city Golden, Colorado, USA, is involved in the research works.

The present stage of power development and its nearest feature is characterized by the necessity in resolution of environmental preservation problems, searches on ways of more economic power consumption, necessity in utilization of new untraditional sources of energy. It seems the most important the possibilities of solar energy, of which most significant advantage is the its ecological purity and practical inexhaustibility. The part of this problem is involved in the tasks being solved in the framework of the given project.

There are lots of ways for the solar energy conversion, from which the photovoltaic and photoclectrochemical techniques are most preferred.

During of the photoelectrochemical (PEC) conversion of solar energy at the expense of solar energy in semiconductor-electrolyte interface the reaction of water photosplitting into molecular hydrogen and oxygen is realized.

Water photosplitting process is activated by means of the corresponding photocatalysts such as in particular photosensitive semiconductor ceramic electrodes. Use of ceramic photoelectrodes in solar energy photoelectrochemical converters provides their low cost price, and it is only necessary to solve the problem of increase in conversion efficiency.

At present wide area of semiconducting photoelectrodes (single crystalline, amorphous, ceramic, thin film, with the various type of conductivity, with the different band gaps and electrophysical parameters) have been studied. The rather complete picture of PEC behavior for semiconducting photoelectrodes based on TiO2, SrTiO3, ZnO and Fe2O3 and the other is developed.

Anyone of researched materials has not the whole set of parameter required for effective photoelectrolysis of water. However, there are not theoretical reasons limiting the possibility of achieving the economical profitable efficiencies for the PEC converters. Therefore, at present, studies carried out on development of new semiconducting materials-catalysts with the required properties, the finding of opportunities for optimization of characteristics of already utilized photoelectrodes and the investigations on complex physicochemical processes taking place at the interface.

The converters of a solar energy, for use of power in needs, in basic, are made from silicon. Si is the most advanced and investigated semiconductor, and at the same time easiest accessible and widespread element in earth core and its using permits the most harmless production solar PVC. These circumstances and their rather low cost price will be doubtless playing a crucial role at large-scale manufacturing and applications for the use of solar photoelectric energy on the Earth and in Space.

The development of the technology and the fabrication of silicon based on new solar cell designs possessing efficiency about 16% with the optimum law cost of the fabrication technology is planed also.

The Project executors have long work experience in the field of solar energy conversion. The researches on photoelectrochemical conversion of solar energy carried out by them have brought certain contribution in understanding of processes taking place both in the semiconductor and at the semiconductor – electrolyte interface and also in improvement of photoelectrons efficiency.

To improve the efficiency of converters on the basis of crystalline Si with p-n-junction a search of new techniques was carried out in area of solar energy photovoltaic converters. Fundamentally new technologies were developed for fabrication of the photovoltaic converters.


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The International Science and Technology Center (ISTC) is an intergovernmental organization connecting scientists from Kazakhstan, Armenia, Tajikistan, Kyrgyzstan, and Georgia with their peers and research organizations in the EU, Japan, Republic of Korea, Norway and the United States.

 

ISTC facilitates international science projects and assists the global scientific and business community to source and engage with CIS and Georgian institutes that develop or possess an excellence of scientific know-how.

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