Research progress on lateral photovoltaic effect in solar cell structural materials

Abstract

Since the discovery of lateral photovoltaic effect, it has aroused significant interest due to its great potential application in high precision light position sensitive detector. Till now, the lateral photovoltaic effect has been studied in a number of different materials and structures and their performance as position sensitive detectors has been evaluated. However, based on the past studies, most researchers tended to choose new materials or structures to study, their preparation methods and techniques were usually not mature and relatively complex, and the working principles were still in need of further discussion and explaination, making them difficult to be widely used in a short period of time. Through the analysis and summary of the previous reported materials and structures, it is found that one of common characteristics of these devices is the presence of built-in electric field, which is a prerequisite for the generation of lateral photovoltaic effect. Fortunately, in all of the research material systems, there is one kind of material system that just meets this condition: that is the solar cell structure material. The working principles and the preparation techniques of it are well known and very mature, and even many structural solar cells have been mass-produced in industry and used in our daily life. Besides, in terms of working principle, solar cell is based on the photovoltaic effect, and the light position sensitive detector is based on the lateral photovoltaic effect, the two effects are closely connected and support each other in principle, more importantly, the research on the lateral photovoltaic effect can further promote the development of the photovoltaic effect; in terms of applications, the solar cell structure material can not only be used in solar cells, but also in position sensitive detector, so that it can be said that the application of this structure material in light position sensitive detectors is a new application transformation of the solar cells. In this work, we give a brief review of our recent work on the lateral photovoltaic effect in several common solar cell structural materials. Firstly, the basic principle of lateral photovoltaic effect is introduced and the theoretical formulas, as well as the key parameters determining the lateral photovoltaic response, are deduced. Then, the lateral photovoltaic effect in Si, a-Si:H, CIGS, Sb2S3, GaAs/AlGaAs structures are discussed. The effects of layer structure, thickness, doping, electrode spacing, operating temperature, external bias, laser wavelength and power on the lateral photovoltaic response and the corresponding mechanisms are analyzed. By comparing the difference and connection between the working principle of photovoltaic effect and lateral photovoltaic effect, the application transformation of solar cell structure material in light position sensitive detector is verified. However, these researches are all at the beginning of the study, the construction and application of the light position sensitive detectors still have a long way to go and a lot of problems are urgently needed to be solved as compared with the wide research and the mature production technology of solar cells. Finally, we discuss the challenges of the application of solar cell structural materials in light position sensitive detectors, and also prospect the future development direction.