InAs/GaSb超晶格红外探测器波长可调范围大、能带工程运用灵活、均匀性好，但其量子效率和暗电流水平受制于少子寿命短、吸收系数低等材料因素。本项目提出新型的“无Ga”InAsP/InAsSb三元合金超晶格材料，其载流子寿命不受Ga相关点缺陷影响，模拟显示工作波段可覆盖短波到长波红外，带边对齐可从Ⅰ型到Ⅱ型灵活调节，是一种潜在的少子寿命长、吸收系数高、光谱可调范围大的新型红外吸收材料。本项目拟利用MOCVD外延生长InAsP/InAsSb超晶格材料，利用微观手段分析锑元素的偏析，通过界面处理抑制其不利影响，实现合金超晶格的高质量生长；结合理论计算探索高吸收系数、高载流子输运特性所需的三元合金组分与带边对齐；最终通过器件指标对比，验证InAsP/InAsSb超晶格材料的理论优势。本项目的顺利展开将推进锑化物外延技术发展，丰富高性能红外探测材料的选择，开创具有自主知识产权的红外探测材料新体系。

Infrared photodetectors based on InAs/GaSb superlattices can cover a broad range of infrared spectrum and their high degree of flexibility in bandgap engineering have also been demonstrated. However, further improvement in their quantum efficiency and dark current density is limited by the relatively low absorbance and the short carrier lifetime associated with the material. In this proposal, the “Ga-free” superlattices based on InAsP/InAsSb ternary alloys will be investigated for its MOCVD growth and its potential use as an efficient infrared absorber. High absorbance is suggested by preliminary calculations due to its near type-I band alignment, while longer carrier lifetime is expected for the absence of Ga-related point defect. Concerns about the segregation of Sb will be addressed by microscopic study and interface treatment to achieve absorber material of high quality; their absorbance and carrier transport properties will be compared under different alloy compositions and band alignments for optimal quantum efficiency; its theoretical advantages against InAs/GaSb will be finally validated by device characterizations. The success of this project shall enrich the portfolio of MOCVD-grown Sb-based infrared materials and attain our advantages in state-of-art infrared detection technologies.