In this paper, we focuse on the36mm×42mm mercury-rich vertical liquid phase epitaxy(VLPE) technique. By modifying the structure of the graphite boat carrying the substrates, the batch growth of large-size double heterojunction materials with dimensions of 36mm×42mm has been achieved. By combining the phase diagram of material growth and the calculated fluiddistribution, the fields of fluid and temperature in the growth area of the material are optimized to meet the development requirements of p-on-n infrared focal plane array detectors. The thickness deviation of the grown material and the electrical performance satisfies our expectation. The overall performance of the material meets the requirements for fabricating large-scale, large-format p-on-n infrared focal plane array detectors.