Radiation Damage Effect Of Two Kinds Of Transducer Materials For Radiative Batteries

Radiation-Voltaic Isotope Battery (RVIB) is a micro electric generater with radiation isotope, semiconductor or inorganic radioluminescence materials, as energy input and conversation devices, including direct radiation voltaic mechnism and raidaiton-voltaic combine photovoltaic mechnism. RVIB is the ideal power source for low power-consuming MEMS and IC systems. In order to realize the properties of long-period working and free of maintance, except for picking up long radioactive half-life isotopes, the energy conversation device should be good at radiation-resistance. The theoretic and experiment investigation of radiaiton damage in RVIB are not mature in china, which can hinder the developing of RVIB.This thesis deploys an initial investigation in low-energy radioactive beta soure(tritium source) loaded radiative damage effect to crystal silicon conversation device. Tritium source is in term of titanium tritide, and the self-absorb of different thickness and the mount of emitting particle were simulated by Monto-Carlo method Geant4software package. The important effect of passivation layer on the same (100)c-silicon are examined by compare experiments design. three kinds of passivation layer, SiO2/Si3N4、B-Si glass/Si3N4、Si3N4, are designed and those respective results of initial property and radiative-resistance property varied a lot under the irradiation of titanium tritide with activity of87G-Bq/cm2. B-Si glass/Si3N4passivation layer got the most optimized property and SiO2/Si3N4structure share the most servere radiation damage, while the Si3N4layer have a poor initial property. Pure x-ray radiation experiment are designed by shield the emitting beta particle with a5mm gap between the source and conversation device, the result show that x-ray radiation can cause more servere damage compare to the beta and x-ray combined radiation, x-ray is the reason for radiation damage and beta have a function of release the damage. Besides, x-ray caused surface radiation stain which is visual with eyesight. After XPS detection, the surface radiation stain sourced from the displain of the interface of passivation layer and energy conversation which was lead by x-ray radiation. ESR and C-V measurement are also used in characterizing the defect in interface, dangling bonds and positive charge defect are increased by radiation, and surface hole depletion layer are formed especially in pure x-ray radiation.Radiative-voltaic and photovoltaic combined conversation mechnism is a new method to solve the problem of radiation damage from high energy particle. Sr was used to irradiate the transparent ceramic, the photon and particle passed through the ceramic interact with the conversation device. Geant4was used for the simulation of the ralationship between the thickness of ceramic and the emitting particles, and find out1mm is the most optimized thickness in our experiment. Experiment and an accelerated aging test with electric radiation are carried out. The result show that the transmission curve of Ce:YAG keep the initial value after14year dose accelerated aging test and the dark current of conversation device change litter due to the protection of ceramic. Meanwhile, fluorescence test is also carried out and the intensity of fluoresence decrease a little. There are different fluorescence intensity under different exciting wave and different doped concentration, and beta-fluorescence is distinguish from photo-fluorescence in mechnism. This mechnism of combined conversation is an effective method to solve the radiation damage from high energy particle in beta-voltaic battery.For the theoretical simulation part, the following conclusions are got:a) In the simulation of radioactive source, titanium tritide source emitting β particles also emission low energy x-ray with characteristic peaks of4.45keV and4.85keV. The β particles emission can reach saturated when increased titanium tritide source thickness to about0.7μm and the x-ray is not saturated with the thickness.For low-energy titanium tritide radiate the monocrystalline part, the following conclusions aregot:b) The x-ray emitted from source of titanium tritide can cause radiation damage in monocrystalline silicon conversation device, but beta can relieve the damage in this process. Essentially, damage came from the destroy of plain surface of monocrystalline silicon. Reducing the amount of x-ray emission is a good way to reduce the radiation damage.c) Surface passivation layer structure has a significant inpact in the initial output performance and radiation resistance. Under a titanium tritide radiation,(100)Si/B-Si glass/Si3N4passivation layer got a good initial output properties and radiation resistance,(100)Si/SiO2/Si3N4structure has the best initial performance and maximum radiation damage,(100)Si/Si3N4structure can not get a good output.For which betavoltaic-photovoltaic Joint Research conversion mechanism, we can draw thefollowing conclusions: d) Radiation-voltaic/Photovoltaic joint mechanism can make efficiently use of high energy particles, and can effectively reduce the radiation damage of the semiconductor conversation device.e) Ce:YAG ceramic has good radiation resistance, after3.2x1017electron fluence (equivalent to14years of Sr radioactive dose) accelerated irradiation with electron accelerator, Ce:YAG basically keep the initial performance, which is a good Radiation-voltaic/Photovoltaic conversion material.