氮化镓/硅复杂界面结构异质结的光伏效应

Photovoltaic Effect of Gallium Nitride/Silicon Complicated Interface Heterojunction

采用宽带隙半导体材料或减小p-n结漏电流密度是增加开路电压以提高太阳能电池光电转换效率的重要途径。氮化镓(GaN)是一种具有直接带隙的宽带隙化合物半导体材料,并已在光电器件领域得到广泛应用。以通过水热腐蚀制备的、具有优异宽波段光吸收性能的硅纳米孔柱阵列(Si-NPA)为功能性衬底,采用化学气相沉积法制备了一种具有复杂界面结构的异质结GaN/Si-NPA,并以此为基础制备了器件结构为ITO/GaN/Si-NPA/sc-Si/Ag的太阳能电池原理性器件。在AM 1.5的模拟太阳光照射下,电池的开路电压达到1.94 V,短路电流密度0.07 mA/cm2,填充因子73%,电池光电转换效率0.1%。对实验结果的分析表明,电池效率较低的原因是较大电池串联电阻导致了较小短路电流密度。本研究为制备具有更高开路电压的高效太阳能电池提供了一种可能的新途径。.

The increasing of the open circuit voltage through adopting wide-bandgap semiconductors or decreasing the leakage current density of p-n junctions was one of the important ways to promote the energy conversion effect of solar cells.Gallium nitride(GaN)was a semiconductor with direct and wide bandgap,which had been widely applied in the field of optoelectronic devices.A silicon-based GaN heterojunction with complicated interface structure was prepared by depositing GaN using a chemical vapor deposition method on silicon nanopoprous pillar array(Si-NPA)prepared by a hydrothermal etching method.Based on the heterojunction of GaN/Si-NPA,a prototype solar cell with a device structure of ITO/GaN/Si-NPA/sc-Si/Ag was developed.Under the irradiation of AM 1.5 simulated sunlight,the open circuit voltage,short circuit current density,the fill factor and the energy conversion efficiency of the solar cell were measured to be 1.94 V,0.07 mA/cm2,73%and 0.1%,respectively.The relatively low cell efficiency was attributed to the very low short circuit current density resulting from the large series resistance.The research provided a new route for preparing high-efficiency solar cells with large open circuit voltage.