Loss analysis of DSBC solar cells on FZ(B), MCZ(B), CZ(Ga), and CZ(B) wafers

Abstract

The experimental performance of the double-sided buried contact (DSBC) solar cell does not reflect the theoretical potential of the device design; instead, it results in suboptimal one-sun performance. Several mechanisms that adversely affect the performance of the DSBC solar cell have previously been identified; however, their impact on performance is still unquantified. Furthermore, since the inception of the DSBC design, the type of silicon available to the commercial silicon solar industry has broadened to include alternative dopants, growth methods, and thinner wafers. This paper investigates the performance limitations of the DSBC design on boron-doped float-zoned, boron-doped magnetically confined Czochralski (CZ), gallium-doped CZ, and boron-doped CZ wafers in terms of 1) manufacturing limitations, 2) design limitations, and 3) wafer-choice limitations. It utilizes in-process characterization tools and extensive cell characterization to identify the loss mechanisms dominating the DSBC design performance on commercial wafers. Finally, a PC1D model is constructed to evaluate the relative importance of these loss mechanisms to the device performance. The results of this loss analysis highlight the importance of the three aspects of high-efficiency silicon solar cells, i.e.,1) manufacturing, 2) design, and 3) wafer selection, both to the future improvement of the DSBC solar cell and other high-efficiency commercial structures.