| Since entering the information age,great changes have taken place in various fields closely related to human life.In some high-precision fields,such as aerospace,precision machine tools,nano ranging and other technologies and equipment,the development of high-precision position sensitive detectors is playing an increasingly important role.At present,people are trying to achieve new progress or breakthrough in the performance of position sensitive detector through a variety of new materials,new methods and new technologies,so as to achieve its leading position in this field and make new contributions to the development of human society.Position sensitive detector is based on the principle of lateral photovoltaic effect.Firstly,it needs to form a built-in electric field inside the material structure,and the intensity of the electric field determines the longitudinal separation and transmission performance of photon-generatedcarriers to a large extent.At the same time,the material should also have good surface conduction.Therefore,the appropriate material selection and structure design are of great importance.Past research has shown that researchers mainly focus on some new materials or structures to clarify their lateral photovoltaic properties and potential applications in position sensitive detectors.However,due to the complex preparation process,immature preparation method,unstable performance and high cost,it is difficult to be applied in a short time.Our research found that,there is a kind of structural materials that can meet the design needs of position sensitive detector in the relatively mature material system,namely solar cell structural materials.It has clear working principle and stable preparation process,and many structural solar cells have been widely used in industry and daily life.Therefore,the structural materials of solar cells are very suitable for the study of lateral photovoltaic effect.At the same time,it shows important potential applications in position sensitive detectors.Among many kinds of solar cells,Cu（In,Ga）Se2（CIGS）thin film solar cells have attracted widespread attention due to their stable performance,strong radiation resistance and high photoelectric conversion efficiency.It also take a place in the fierce photovoltaic industry.Based on CIGS thin film solar cells,this paper studies the lateral photovoltaic effect.Firstly,by drawing upon the cell’s multilayered structure and changing the thickness of the conductive layer,the influence factors and control mechanism of photon-generated carrier diffusion process in the lateral photovoltaic effect were clarified.Secondly,based on the lateral photovoltaic work,the lateral photocurrent was studied to reveal the lateral photovoltaic effect.Thirdly,the special carrier conduction process in the lateral photovoltaic effect is analyzed.By using this carrier,the effective control of the carrier movement in the conduction layer under the external lateral bias is realized,and the position sensitive detector and optical storage device based on the lateral photoresist are studied.Finally,the preliminary results are given the lateral photovoltaic effect in the flexible CIGS solar cell structure is studied,which provides an important basis for the development of flexible position sensitive detector.The details are as follows:（1）In order to understand the effect of conductive layer on the lateral photovoltaic effect and the influence of the thickness of conductive layer on the lateral photovoltaic effect,we designed CIGS heterojunction samples（10-150 nm）with different ITO layer thickness by using the characteristics of CIGS multilayer structure.We studied the influence of the transverse diffusion process on the lateral photovoltaic effect and its time response characteristics by changing the different laser wavelengths and power.The results show that the lateral photovoltaic response increases rapidly with the decrease of ITO layer thickness,but the response speed remains almost unchanged.This study provides an important basis for revealing the influence of the lateral diffusion process on the lateral photovoltaic effect in the CIGS multilayer heterojunction.Meanwhile,it provides a very simple and effective method for regulating lateral photovoltaic performance in other multilayer heterostructures.（2）We studied the lateral photocurrent effect in CIGS multilayer structure and explored the influence of ITO layer thickness.In the lateral photovoltaic effect,the transverse diffusion of the photocarriers also produces the diffusion current.Thereby the photoelectric devices based on the lateral photocurrent mode can be developed.By changing the laser wavelength,power and electrode spacing,the lateral photocurrent response in CIGS multilayer structure is studied in detail,and the influencing factors and regulation mechanism are revealed.According to the principle of lateral photocurrent,CIGS multi-layer heterojunction can be developed into a wide band high performance self driving position sensitive detector and photoelectric detector based on the lateral photocurrent effect.This study not only reveals the important influence and regulation relationship of carrier separation,transmission and collection in the multi-layer solar cell structure,but also provides the basis for the development of other new photoelectric devices based on the lateral photocurrent effect.（3）We studied the lateral photoresistance effect in CIGS multilayer heterostructuresx.Considering the existence of the lateral diffusion carriers in the lateral photovoltaic effect,when the applied bias voltage is applied between the two electrodes,the diffusion carriers will inevitably regulate the drift carriers in the conduction layer,thus affecting the layer resistance,which is of great significance for the resistor devices with light-emitting regulation.By changing the laser wavelength,power,bias voltage and polarity,the lateral photoresistance property in CIGS multilayer heterostructures are systematically studied.The influencing factors and variation rules are found,and the phenomenon is successfully explained by theoretical derivation and model establishment.Based on the lateral photoresistance effect,the heterojunction can be developed as a lateral photoresistance controlled position sensitive detector and storage device.（4）CIGS multilayer heterostructures are fabricated on flexible PI substrates,which show the same lateral photovoltage and photocurrent characteristics.Through the performance test before and after bending,it is found that the device has relatively stable response performance,which lays an important foundation for the further development of flexible CIGS position sensitive detector.In conclusion,we have systematically studied the lateral photovoltaic effect,lateral photocurrent effect and lateral photoresistance effect of CIGS multilayer heterostructures.This research not only broadens the new material system of position sensitive detector,but also plays a positive role in promoting the cross research of CIGS solar cell and position sensitive detector,and provides important reference value. |
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