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Interaction Between Electromechanical Field And Carrier In Typical Piezoelectric Semiconductor Structures

Posted on:2020-02-22Degree:DoctorType:Dissertation
Country:ChinaCandidate:S Q FanFull Text:PDF
GTID:1368330590958974Subject:Solid mechanics
Abstract/Summary:PDF Full Text Request
Piezoelectric media can be divided into insulators and semiconductors usually and the former is often utilized as power conversion and sensing due to that there does not exist free charges in the media;the latter possesses both power conversion and wave-particle drag effect and the piezoelectric potential will be arose when the stress wave propagates in the media and induces the ions polarization.And further the piezoelectric potential will interact with the carriers in the semiconductor and then drive them redistribution.Obviously,the applying of mechanical field and acoustic wave can adjust or control the property of carrier redistribution effectively,therefore,new microelectronic devices with modern function can be developed and there will be a significant application prospects in the field of micro-electro-mechanical system,nanorobot,human-computer interaction,micro-nano sensing and biological terrorism.In this paper,a systematic and deep study on typical piezoelectric semiconductor structures existing in piezoelectric electronic devices is carried out,the interaction property of electromechanical field and carrier is illuminated as well as the regulate law of electrical properties for external mechanical load on the typical structures of piezoelectric semiconductor is revealed.The main results achieved are as follows:1.Starting from the coupling of electromechanical-carrier,the model of n-type ZnO nanogenerator whose c-axis along the axis of the nanowire is established.Due to the irrotationality of static electric field,it is indicated that the electric field intensity can do nothing to the stresses on the cross-section of a bent nanowire.And we find that the piezoelectric potential will increase the carrier concentration on the stretch side and reduce the carrier concentration on compressive side and then weaken the polarization electric field.Calculation results show that a higher carrier concentration often corresponds to a stronger weaken effect,indicating that the semiconducting property will induce current leakage of ZnO nanogenerator.Therefore,a smaller doping concentration does improvement for the performance of nanogenerator.2.The mechanical model on the coupling of multi-field for piezoelectric semiconductor nanofiber under typical forms of load is established.The distribution law of potential barrier and well is obtained and the distribution property of carrier and polarization is also illuminated.This achieved special potential barrier and well by typical forms of load have a significant meaning to the development of piezoelectric electronic and piezoelectric photonic devices.3.The model of piezoelectric PN junction under symmetry mechanical load is established.The basic equations on the coupling of electromechanical for piezoelectric PN junction are obtained and the effects of external mechanical load on electrical properties are studied.The results indicate that symmetry tensile stresses increase the width of space charge zone and potential barrier while compressive stresses reduce the width of space charge zone and potential barrier.Besides,the closer the load position is to the space charge zone,the more obvious the regulating effect of the load on the electrical performance of the PN junction.4.The model of piezoelectric PN junction fixed at the interface of p-zone and n-zone under asymmetry mechanical load is established.The results show that even though the load positions are far from space charge zone,asymmetry mechanical loads can still do significant effect on electric parameters at the interface due to the existence of concentrate stress at the position where it is fixed.Besides,the width of space charge zone on both sides of the interface no longer remains the same and the law of how electric potential and electric field vary is also changed on both sides of the interface.Those results can do some referential meaning to the control of fundamental properties of piezoelectric PN junction by external mechanical load.In this paper,the interaction between electromechanical field and carrier in the piezoelectric semiconductor structures is analyzed,the law of adjust and control on the electrical properties of typical structures of piezoelectric semiconductor by the way of mechanics is revealed.Research findings exert significant theoretical meaning on broaden and further development of elastic wave theory and also do some promoting to the research,development and application of new piezoelectric electronic and piezoelectric photonic devices.
Keywords/Search Tags:piezoelectric semiconductor, interaction between electromechanical field and carrier, piezoelectric potential, carrier, piezoelectric PN junction, ZnO nanowire
PDF Full Text Request
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