CN108492905A - A kind of diamond PIM Schottky types β radiation volta effect nuclear battery - Google Patents

Abstract

The invention discloses a diamond PIM Schottky type beta radiation volt effect nuclear battery, the basic structure of which includes: a pure beta radiation source provides energy-carrying beta particles; a diamond moderator moderates the high-energy beta particles emitted by the pure beta radiation source Obtain low-energy β particles; diamond PIM Schottky diodes absorb energy-carrying β-particles and convert their energy into electrical energy; the battery casing protects the internal structure of the battery and shields unused energy-carrying β-particles and secondary γ-rays. Due to the characteristics of diamond materials such as large band gap, strong radiation resistance, high-doped diamond electrical properties, high temperature resistance, high pressure resistance and extremely high chemical inertness, the energy conversion of β-radiation volt effect nuclear batteries based on diamond materials High efficiency, stable output, long service life and simple protection.

Description

A kind of diamond PIM Schottky type beta radiation voltaic effect nuclear battery

technical field

The invention relates to a battery device for converting the decay energy of radionuclides into electric energy by using semiconductor devices, and belongs to the technical field of nuclear energy utilization.

Background technique

In recent years, with the advancement of science and technology, the research and development and application of MEMS have developed rapidly. They generally have the characteristics of small size, low power, light weight, easy to move, stable performance, low cost and implantability. However, further development of MEMS has been limited by the lack of tiny power sources. Common miniature power sources include miniature fuel cells, miniature chemical batteries, miniature internal combustion engines, and miniature solar cells. However, none of these tiny batteries are well suited to meet the tiny power requirements of MEMS devices. First of all, miniature fuel cells, miniature chemical batteries and miniature internal combustion engines need to be constantly supplemented with fuel from the outside or intermittently charged. At the same time, their energy conversion efficiency is low and it is difficult to miniaturize to the micron or even nanometer level required by MEMS. Secondly, although solar cells have the characteristics of cleanness, safety, and mature technology, and can be miniaturized to the micron or even nanometer level by using micro-nano processing technology, they cannot work normally in dark or unstable sunlight environments. Finally, the nuclear battery has become an ideal choice for MEMS power supply due to its characteristics of miniaturization, integration, high energy density, long service life and no dependence on external energy.

At present, the β-radiation volt effect nuclear battery based on semiconductor devices (PN junction, PIN junction and Schottky diode) has been used in aerospace exploration, deep-sea deep-ground exploration, meteorological monitoring in harsh environments such as mountains and polar regions, and medical instruments. application. The working principle of this type of nuclear battery is: when the energy-carrying β particles interact with the semiconductor material, a large number of electron-hole pairs will be generated, and the built-in electric field of the semiconductor device will deplete the radiated electron-holes in the layer. The charge collection efficiency was 100% for all sweeping out of the region after separation. The radiant electron-hole pairs outside the depletion layer can be separated and collected by the electrodes only when they diffuse into the depletion layer. Therefore, the charge collection efficiency in the area outside the depletion layer is low. Beta radiation The radioactive source in the voltaic effect nuclear battery is generally pure beta decay and the energy of the beta particles released by it is relatively low. Pure diamond is a good insulator with high resistivity, but the resistivity of doped diamond will drop by many orders of magnitude to make it a typical semiconductor material. It has a large band gap and saturated carriers (electrons and holes) High mobility, good thermal conductivity and chemical inertness, high electron density, and strong radiation resistance. The research results show that these advantages of diamond materials are helpful to improve the service life and energy conversion efficiency of β-radiation voltaic effect nuclear batteries. In particular, diamond Schottky diodes are ideal for beta radiation voltaic effect nuclear cells.

Contents of the invention

The invention provides a volt effect nuclear battery based on diamond PIM Schottky type β radiation, which uses a mature preparation process to process and integrate a pure β radiation source, a diamond moderator and a diamond PIM Schottky diode into a radioactive source A device that converts decay energy into electrical energy. This type of nuclear battery has become an ideal micro power supply for MEMS because of its high energy conversion efficiency, strong radiation resistance, stable output and long service life.

In order to achieve the above object, the technical solution of the present invention is:

A diamond PIM Schottky type beta radiation voltaic effect nuclear battery (see accompanying drawing 1 and accompanying drawing description).

The pure beta radiation source (1) is a lamellar cylindrical solid radiation source. Tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) or strontium-90 source ( ⁹⁰ Sr) is selected. Further, considering that the β radiation originates from the absorption effect, the thickness of the tritium source (Ti ³ T _X ) is less than 2 μm; the thickness of the nickel-63 source ( ⁶³ Ni) is less than 3 μm; the thickness of the promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) Less than 43 μm; the thickness of the strontium-90 source ( ⁹⁰ Sr) is less than 1 cm.

The detachable diamond moderator (2) is cylindrical, and its radius is the same as that of the pure beta radiation source (1). Changing the thickness of the diamond moderator (2) moderates the high-energy beta particles emitted by the pure beta radiation source to obtain low-energy beta particles that are lower than the energy threshold of the diamond PIM Schottky diode against radiation damage and meet the output power requirements of the micro-electromechanical system. Further, in the nuclear battery corresponding to the tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr), diamond The thicknesses of moderators (2) are respectively less than 0.2 μm, 23 μm, 50 μm and 3.2 mm. Among them, the diamond moderator (2) is mainly used in nuclear batteries corresponding to promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr).

The diamond PIM Schottky diode is cylindrical, and its radius is the same as that of the pure beta radiation source (1), and its interior is sequentially stacked to form a P-type highly doped diamond substrate layer (3), a P-type low-doped diamond buffer layer (4), intrinsic diamond layer (5) and Schottky electrode layer (6).

The P-type highly doped diamond substrate layer (3) is a (001)-oriented boron-doped diamond layer with a thickness of less than 200nm and doped boron atomic concentration N _A >1×10 ¹⁸ cm ^-3 ; further, the P-type highly The doped diamond substrate layer (3) is the implanted front electrode of the nuclear battery.

The P-type low-doped diamond buffer layer (4) is a (001)-oriented diamond epitaxial layer, doped with a concentration of boron atoms N _A <1×10 ¹⁴ cm ^-3 , and a thickness of less than 20nm.

In the nuclear battery corresponding to the tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr), the intrinsic diamond ( 5) The thicknesses are less than 0.2 μm, 23 μm, 50 μm and 3.2 mm, respectively.

The Schottky electrode layer (6) is a field plate structure with a thickness less than 30nm. Further, the Schottky electrode layer (6) is a single metal layer or a metal composite layer composed of a plurality of single metal layers formed from multiple metals. Furthermore, the work function of the metal material in the metal layer in the Schottky electrode layer (6) in contact with the intrinsic diamond layer (5) is smaller than the band gap of diamond.

The P-type highly doped diamond substrate layer (3) and the Schottky electrode (6) are respectively provided with a first lead and a second lead correspondingly, and after annealing, they are packaged to obtain a diamond PIM Schottky diode.

The battery case (7) and its detachable part (8) are cube structures. Further, the battery casing (7) and its detachable part (8) are made of high molecular polyethylene plastic with low density, and the thickness is less than 1.5cm.

In summary, combined with the self-absorption effect of the radioactive source, the ionization range of the radioactive source in the transducing material, the preparation technology and radiation protection of the diamond PIM Schottky diode, the present invention provides a diamond PIM Schottky diode A technical proposal for a β-radiation volt effect nuclear battery. The technical solution greatly improves the energy conversion efficiency and energy output power of the nuclear battery, prolongs the service life of the nuclear battery, and has stable performance of the nuclear battery.

Description of drawings

Fig. 1 is a schematic axial cross-sectional view of the diamond PIM Schottky type beta radiation voltaic effect nuclear battery. Marks in the figure: (1) is a pure β radiation source, (2) is a detachable diamond moderator, (3) is a P-type highly doped diamond substrate layer, (4) is a P-type low-doped diamond buffer layer, (5) is the intrinsic diamond layer, (6) is the Schottky electrode layer, (7) is the battery case, and (8) is the detachable part of the battery case.

Fig. 2 is the top view of described a kind of diamond PIM Schottky type beta radiation voltaic effect nuclear battery;

Detailed ways

The main content of the research on the β radiation volt effect nuclear battery includes: the self-absorption effect of the β radiation source, the backscattering of the energy-carrying β particles on the surface of the material, the ionization range of the energy-carrying β particles in the energy-transforming material, the preparation process of the nuclear battery and Research on output performance of nuclear battery. The research results show that: the diamond Schottky diode is an ideal transducing device for the β-radiation volt effect nuclear battery.

The energy-carrying beta particles decayed by the beta radioactive source interact with the radioactive source itself to produce self-absorption. This phenomenon leads to the fact that with the increase of the thickness of the β-radiation source, its surface output power first increases continuously and then tends to a saturated value. Generally, tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr ) emit The thickness corresponding to the source is about 2 μm, 3 μm, 43 μm and 1 cm respectively. Therefore, the thickness of the cylindrical solid sheet-shaped pure beta radiation source (1) in the present invention is smaller than the corresponding thickness when the surface output power reaches the saturation value. That is to say, the thickness of the tritium source (Ti ³ T _X ) is less than 2 μm; the thickness of the nickel-63 source ( ⁶³ Ni) is less than 3 μm; the thickness of the promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) is less than 43 μm and the strontium- The thickness of the 90 source ( ⁹⁰ Sr) is less than 1 cm.

In order to moderate the high-energy beta particles emitted by the pure beta radiation source to obtain low-energy beta particles that are lower than the energy threshold of the diamond PIM Schottky diode against radiation damage and meet the output power requirements of the micro-electromechanical system, diamond moderators are set in the nuclear battery body. Generally, the ionization ranges of tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr) in diamond materials are respectively It is about 0.2μm, 23μm, 50μm and 3.2mm. Therefore, in the nuclear battery corresponding to tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr) in the present invention The thicknesses of the diamond moderators (2) with adjustable thickness are respectively less than 0.2 μm, 23 μm, 50 μm and 3.2 mm. Furthermore, the diamond moderator (2) is mainly used in nuclear batteries corresponding to promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr).

In order to optimize the performance based on the diamond Schottky diode type beta radiation voltaic effect nuclear battery, a P-type highly doped diamond film is used as an implanted electrode to reduce the backscattering energy loss of energy-carrying β particles on the surface of the nuclear battery transducing device; further, compared to the N-type diamond film, using the P-type diamond film as the emission layer of the nuclear battery can effectively improve the nuclear battery Internal charge collection efficiency; Furthermore, matching the ionization range of the beta radiation source inside the transducer device with its intrinsic layer area is a key issue in improving the nuclear battery. Finally, compared to metals with higher work functions, metals with lower work functions will help increase the height of the P-M diamond Schottky barrier, reduce the leakage current of the diamond Schottky diode, and increase the open circuit voltage of the nuclear battery and energy conversion efficiency.

The diamond PIM Schottky diode is sequentially stacked to form a P-type highly doped diamond substrate layer (3), a P-type low-doped diamond buffer layer (4), an intrinsic diamond layer (5) and a Schottky electrode layer (6), its main preparation method is as follows:

Step 1: Synthesize a P-type highly doped diamond substrate layer (3) by chemical vapor deposition technology, its crystal orientation is (001), the thickness is less than 200nm, and the doping concentration of boron atoms is N _A >1×10 ¹⁸ cm ^-3 . Further, the P-type highly doped diamond substrate layer (3) is the implanted front electrode of the nuclear battery.

Step 2: Using chemical vapor deposition technology to epitaxially grow a P-type low-doped diamond buffer layer (4) on a P-type highly-doped diamond substrate layer (3), doped with a concentration of boron atoms N _A <1×10 ¹⁴ cm ^-3 , the thickness is less than 20nm.

Step 3: using chemical vapor deposition technology to epitaxially grow an intrinsic diamond layer (5) on the P-type low-doped diamond buffer layer (4) prepared in step 2. Further, the intrinsic diamond layer (5) is matched with the ionization range of the pure β radiation source in diamond, therefore, the tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), In nuclear batteries corresponding to promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr), the thickness of the intrinsic diamond layer (5) is less than 0.2 μm, 23 μm, 50 μm and 3.2 mm, respectively.

Step 4: Surface treatment is performed on the intrinsic diamond layer (5) prepared in step 3 to form an oxygen terminated surface state. Further, the surface was cleaned with acetone, deionized water and ultrasonic waves.

Step 5: The Schottky electrode layer 6 is a field plate structure with a thickness less than 30 nm. The surface of the intrinsic diamond layer (5) prepared by electron beam evaporation coating technology in step 4 is deposited on the surface of a metal single metal layer (such as metal hafnium) with a work function smaller than the diamond band gap width to form a Schottky electrode layer (6), or A metal composite layer of a plurality of single metal layers (such as titanium, nickel, platinum, gold, aluminum) is deposited on a metal layer (such as metal hafnium) whose work function is smaller than the band gap of diamond to form a schottky electrode layer (6).

Step 6: Correspondingly setting a first lead and a second lead on the P-type highly doped diamond substrate layer (3) and the Schottky electrode (6). Further, the annealing treatment of the diamond PIM Schottky diode is completed under the protection of nitrogen atmosphere. Furthermore, the diamond PIM Schottky diode is packaged.

The battery case (7) and its detachable part (8) are cube structures. Further, the battery casing (7) and its detachable part (8) are made of high molecular polyethylene plastic with low density, and the thickness is less than 1.5cm.

The specific embodiments described in the present invention describe in detail the theoretical basis and specific technical solutions for the design of a diamond PIM Schottky type beta radiation voltaic effect nuclear battery. It should be noted that the above descriptions are only specific examples of the present invention, and are not intended to limit the design and manufacture of the nuclear battery of the present invention. Further, within the spirit and principles of the present invention, any modifications, equivalent replacements, improvements, etc. are included in the protection scope of the present invention. Furthermore, for simplicity and clarity in the description of the present invention, the drawings only illustrate general structures, omitting some well-known structures to avoid unnecessary ambiguity, and the cross-sections of the drawings are not drawn strictly according to actual scale.

Claims (8)

1. A diamond PIM Schottky type beta radiation volt effect nuclear battery is characterized in that said nuclear battery comprises a pure beta radiation source (1), a removable diamond moderator (2), and a diamond PIM Schottky diode inside The layers are sequentially stacked to form a P-type highly doped diamond substrate layer (3), a P-type low-doped diamond buffer layer (4), an intrinsic diamond layer (5), a Schottky electrode layer (6), and a battery casing (7) and its removable part (8). 2. a kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1 is characterized in that, pure β radiation source is selected as tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni ), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr), the thicknesses of which are less than 2 μm, 3 μm, 43 μm and 1 cm, respectively. 3. a kind of diamond PIM Schottky type β radiation voltaic effect nuclear battery according to claim 1, is characterized in that, the thickness of detachable diamond moderator is between tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr) are smaller than 0.2μm, 23μm, 50μm and 3.2mm respectively in the nuclear battery. Further, the diamond moderator mainly It is used in nuclear batteries corresponding to promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr). 4. a kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1 is characterized in that, its diamond PIM Schottky diode is characterized in that, adopts chemical vapor deposition technology to synthesize P-type highly doped diamond The substrate layer is a (001)-oriented boron-doped diamond layer, the thickness of which is less than 200nm, and the concentration of doped boron atoms is N _A >1×10 ¹⁸ cm ^-3 . In addition, the P-type highly doped diamond substrate layer is the nuclear battery implantable front electrodes. 5. A kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1, is characterized in that, its diamond PIM Schottky diode is characterized in that, adopts chemical vapor deposition technology to prepare P-type low-doped diamond The buffer layer is a (001)-oriented boron-doped diamond epitaxial layer, doped with a concentration of boron atoms N _A <1×10 ¹⁴ cm ^-3 , and a thickness less than 20nm. 6. a kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1 is characterized in that, its diamond PIM Schottky diode is characterized in that, adopts chemical vapor deposition technology to prepare intrinsic diamond layer, will The thickness of the intrinsic diamond layer matches the ionization range of the pure β radiation source in diamond, specifically, the thickness of the intrinsic diamond layer is within the range of the tritium source (Ti ³ T _X ), nickel-63 source ( ⁶³ Ni ), promethium-147 source ( ¹⁴⁷ Pm ₂ O ₃ ) and strontium-90 source ( ⁹⁰ Sr) are smaller than 0.2μm, 23μm, 50μm and 3.2mm respectively in the nuclear battery. 7. A kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1, is characterized in that, its diamond PIM Schottky diode is characterized in that, described Schottky electrode layer is field plate structure, Thickness is less than 30nm, using electron beam evaporation coating technology to deposit a single metal layer (such as metal hafnium) with a work function smaller than the diamond band gap on the surface of the intrinsic diamond layer to form a Schottky electrode layer, or when the work function is smaller than the diamond band gap A metal composite layer of multiple single metal layers (such as titanium, nickel, platinum, gold, aluminum) is deposited on a single metal layer (such as metal hafnium) with a width of 100 to form a Schottky electrode layer. 8. A kind of diamond PIM Schottky type β radiation volt effect nuclear battery according to claim 1, is characterized in that, its battery casing and its detachable part are cube structures, and it is made of the little macromolecular polyethylene plastics of density Composition, the thickness is less than 1.5cm.