SBIR PHASE I: Metalorganic Chemical Vapor Deposition (MOCVD)-Grown InT1P Long Wavelength Infrared Detectors

这个小企业创新研究第一阶段项目研究了一种新材料磷化铟铊（InTlP），该材料被建议作为碲镉汞（HgCdTe）的替代品，用于红外焦平面阵列应用的长波长红外（8至12微米）探测器。理论计算表明，向InP中添加Tl可以将InP的带隙从1.35eV（0.9微米）减小到小于0至0.1eV，即，大约8到12微米。虽然这些理论预测还有待验证（因为InTlP还没有通过任何生长技术制成），但是InTlSb的初步结果已经证明，InTlSb膜可以通过金属有机化学气相沉积（MOCVD）生长，并且向InSb中添加Tl可以将带隙减小到0.15eV（8微米）。预期InTIP具有优于InTlSb的上级性质，包括在整个合金相图上的完全固溶度、与InP的近晶格匹配以及用于集成检测器阵列和InP读出电路的潜力。此外，与HgCdTe和III-V量子阱红外光电探测器（QWIP）相比，InTlP提供了许多潜在的优点;与HgCdTe相比，它具有更高的机械强度、更低的衬底成本和更好的成分均匀性。与QWlPs相比，它提供了正入射检测和更高的量子效率。 第一阶段的目标是证明在两个不同的波长超过2微米（小于0.5 eV）的InTlP光电导探测器。 基于Tl基合金的高性能探测器将为HgCdTe红外焦平面阵列提供低成本的替代品。除了产生一类新的更经济的红外探测器外，这种材料系统还可用于在中波长红外（MWIR）和长波红外（LWIR）区域工作的激光器，以及工业和生物医学热成像。

This Small Business Innovation Research Phase I project examines a new material, indium-thallium-phosphide (InTlP), which has been suggested as an alternative to mercury-cadmium-telluride (HgCdTe) for long wavelength infrared (8 to 12 micrometers) detectors for infrared focal plane arrays applications. Theoretical calculations suggest that addition of Tl to InP can reduce the bandgap of InP from 1.35 eV (0.9 micrometers) to less than 0 to 0.1 eV, i.e., around 8 to 12 micrometers. Though these theoretical predictions have yet to be verified (since InTlP has not been made by any growth technique), preliminary results for InTlSb have demonstrated that InTlSb films can be grown by metalorganic chemical vapor deposition (MOCVD) and that addition of Tl to InSb can reduce the bandgap to 0.15 eV (8 micrometers). InTIP is expected to have properties superior to InTlSb, including complete solid solubility over the entire alloy phase diagram, a near lattice-match to InP, and the potential for integration of detector arrays and InP read-out circuitry. Further, InTlP offers many potential advantages over HgCdTe and III-V quantum well infrared photo-detectors (QWIPs); it has higher mechanical strength, lower substrate cost, and better compositional uniformity than HgCdTe. In comparison to QWlPs, it offers normal incidence detection and higher quantum efficiency. The objective of Phase I is to demonstrate InTlP photoconductive detectors operating at two different wavelengths beyond 2 micrometers(less than .5 eV). High performance detectors based on Tl-based alloys will provide a low-cost replacement for HgCdTe infrared focal plane arrays. In addition to yielding a new class of more economical IR detectors, this material system can be useful for lasers operating in the mid-wavelength infrared (MWIR) and long-wavelength infrared (LWIR) regions, and for industrial and biomedical thermography.