CN1705139A

CN1705139A - A series of semiconductor material

Info

Publication number: CN1705139A
Application number: CN 200410044325
Authority: CN
Inventors: 陈文通; 郭国聪; 李强; 王明盛; 徐玲; 蔡丽珍
Original assignee: Fujian Institute of Research on the Structure of Matter of CAS
Current assignee: Fujian Institute of Research on the Structure of Matter of CAS
Priority date: 2004-05-25
Filing date: 2004-05-25
Publication date: 2005-12-07
Anticipated expiration: 2024-05-25
Also published as: CN100492668C

Abstract

A series of semiconductor material and preparation thereof, which refers to CdHg5Q5X4 (Q=S Se Te, X=Cl Br, I), space group is Cmm2(No35), unit cell parameter is a=16.7-17.9 b=8.8-10.0 c=9.1-10.2 alpha=beta=gamma=90 degree Z=4, unit cell volume V=1500-2000, said crystal can be used in dc electricity transmission, solar energy cell and photoelectric switch etc field.

Description

Series of semiconductor materials

Technical Field

The invention relates to a novel semiconductor material series CdHg₅Q₅X₄(Q＝S，Se，Te；X＝Cl，Br，I)。

Background

Semiconductors play an increasing role not only in computers and communications, but also in modern energy technologies (e.g. direct current transmission, solar cells, etc.) in huge, irreplaceable roles.

The semiconductor is mainly used for long-distance high-power transmission in direct-current transmission, and has the remarkable advantages that: when the same power is transmitted, the cost is low, three lines are needed for alternating current, only two lines are needed for direct current, and the structure of a circuit pole is simpler than that of alternating current; the power loss is small in the power transmission process, impedance formed by a capacitor and an inductor is avoided, and only resistance loss exists; the interference to electromagnetic waves is small; is not limited by phase synchronization; and so on. Due to the above advantages, direct current transmission is becoming more and more widely used. For example, in China, the power transmission of the Gezhou dam power station to the east and the Guangdong adopts direct current 50 ten thousand volts, and the three gorges in the Yangtze river also adopts direct current power transmission.

People find the photosensitization phenomenon of selenium as early as 1873, and the solar cell made of selenium can generate current by illumination, so that people feel that the direct power generation by solar energy is very attractive. However, after years of research, the photoelectric conversion efficiency of the power generation in the mode is not more than 1%. In order to improve the photoelectric conversion efficiency of solar direct power generation, people make continuous efforts. By 1954, the photoelectric conversion efficiency is improved to 10%. In 1958, in 3 months, the united states satellite Vanguard-1 was first fitted with solar cells and operated continuously for 8 years. Solar cells are almost installed on artificial celestial bodies that are to be emitted later. The solar cell has light weight and long service life, does not need fuel supply, and gains the firm position of no competitor in the development of the universe. The solar cell itself has been developed greatly, and research and development work mainly focuses on improving the photoelectric conversion efficiency of the cell and overcoming the degradation of photoelectric performance caused by irradiation.

At present, in addition to the existing silicon single crystal solar cells, solar cells such as polycrystalline silicon, cadmium sulfide, cadmium telluride, arsenic graft, selenium indium copper and the like are researched and developed. However, until now, solar cells have not been generally used, on the one hand, because the photoelectric conversion efficiency thereof is still to be further improved, and on the other hand, because the power generation cost thereof is too high. For this reason, it is still significant to develop a semiconductor material that can be used for a solar cell having high photoelectric conversion efficiency and low power generation cost.

In order to fully utilize solar energy and improve photoelectric conversion efficiency, a compound with a band gap width of 1.35eV is the best choice. The photoelectric conversion efficiency of the following two compounds is high: CuInSe₂(CIS) has a photoelectric conversion efficiency of 17% and a band gap of 17%The width is 1.04 eV; the photoelectric conversion efficiency of CdTe (II-VI) is 15.8%, and its band gap width is 1.50 eV. Our work is to provide a new idea for studying this type of photoelectric conversion material by studying new compounds of composition and structure to synthesize compounds having a band gap width close to 1.35 eV.

Since the recent years, the research on semiconductor materials has progressed rapidly, and many semiconductor materials having different band gap widths have been synthesized.

Disclosure of Invention

The object of the invention is to find a semiconductor material with a large "tailorable" band gap width. For this reason, it is necessary to select appropriate elements for synthesizing a new class of compound semiconductors.

We select VIA group element Se, VIIA group element Br and IIB group Cd and Hg, and synthesize the new semiconductor material compound CdHg by solid phase reaction method₅Se₅Br₄. Because the same group elements in the periodic table have similar properties, S or Te elements can be selected to replace Se, Cl or I to replace Br elements, reactants with corresponding mass are accurately weighed according to the molar ratio of each reactant in the reaction formula, and the reactants react for a period of time at a certain temperature range to obtain heterogeneous and isomorphous series compounds CdHg₅Q₅X₄(Q ═ S, Se, Te; X ═ Cl, Br, I), e.g. CdHg₅S₅Br₄，CdHg₅Te₅Br₄，CdHg₅Se₅Cl₄And the like. Meanwhile, due to the difference of the same group elements, the band gap widths of the series of semiconductor materials are different, so that the semiconductor materials with different band gap widths can be obtained by adjusting the components of the materials so as to meet the requirements of different application fields.

New semiconductor material compound Cdyg Hg₅Q₅X₄(Q ═ S, Se, Te; X ═ Cl, Br, I) has the following advantagesPoint: the preparation of the compound is simple and easy, no impurity is introduced in the reaction process, and purification is not needed as long as a sufficiently pure reagent is used; can be relatively mildThe preparation under the condition of (1) does not need complex equipment; the single crystal can be directly obtained without further growth of the single crystal.

Detailed Description

Cdyg Hg as a compound of semiconductor material₅Se₅Br₄Synthesis and single crystal growth of (1):

semiconductor material compound Cdyg Hg₅Se₅Br₄The synthesis and the single crystal growth are simultaneously completed by a solid-phase reaction method. The reaction formula is as follows:

the chemical reagents and the manufacturers are as follows:

HgBr₂ May &baker (England) purity is more than or equal to 99.95 percent

The purity of the Se powder Sichuan semiconductor material factory is more than or equal to 99.999 percent

The purity of Cd powder Shanghai chemical reagent company is more than or equal to 99.999 percent

The material feeding amount of the three reagents is as follows:

HgBr₂ 0.5mmol 0.1802g

se powder 0.7mmol 0.0553g

Cd powder 0.1mmol 0.0112g

The specific operation steps are as follows:

accurately weighing reactants with corresponding mass according to the molar ratio of each reactant in the reaction formula, putting the reactants into a mortar for uniform grinding, tabletting the ground mixture, and filling the tabletting mixture into a glass tube. The glass tube was evacuated and then closed with a flame. And (3) putting the sealed glass tube into a muffle furnace, controlling the temperature by using a temperature controller, heating the glass tube to 200 ℃ within 4 hours from room temperature, keeping the temperature at 200 ℃ for 12 hours, heating the glass tube to 300 ℃ within 5 hours, keeping the temperature at 300 ℃ for 144 hours, cooling the glass tube to room temperature within 48 hours, and then turning off the power supply. The glass tube is taken out of the muffle furnace and opened to obtain yellow block crystals with the maximum size of 1.2mm multiplied by 1.0mm multiplied by 0.6mm.

The compound CdHg is determined by the single crystal structure₅Se₅Br₄The space group of (c) is cm 2(No35). unit cell parameters a is 17.56(4) Å, b is 9.41(2) Å, c is 9.78(2) Å is β γ is 90 °, Z is 4, and unit cell volume V is 1829.79 Å³Ultraviolet-visible spectrum testing shows that the compound CdHg₅Se₅Br₄Has a forbidden band width of about 1.63 eV.

Claims

1. A series of semiconductor materials, characterized by: cdyg Hg₅Q₅X₄The space group (Q ═ S, Se, Te; X ═ Cl, Br, I) is Cmm2(No35), the unit cell parameters are a ═ 16.7-17.9 Å, b ═ 8.8.8-10.0 Å, c ═ 9.1-10.2 Å ═ β ═ gamma ═ 90 DEG, Z ═ 4, the unit cell volume V ═ 1500-2000 Å³。

2. A method of preparing a semiconducting material according to claim 1, characterized in that: by solid-phase reaction, using HgX₂Q powder and single Cd, vacuum sealing, heating, reacting and synthesizing to prepare single crystal.

3. The method of claim 2, wherein: by solid-phase reaction, using HgX₂Powder Q, elemental Cd, synthesized according to the method described in claim 2 and used for the simultaneous preparation of single crystals.

4. Use of a semiconducting material according to claim 1, characterized in that: the crystal is used for direct current transmission.

5. Use of a semiconducting material according to claim 4, characterized in that: the crystal is used for a solar cell.

6. Use of a semiconducting material according to claim 4, characterized in that: the crystal is used for photoelectric switches.