This lecture will focus on polycrystalline lead chalcogenide materials and devices used as mid-infrared photoconductors. Their room temperature processing properties enable integration with back-end Si-CMOS, and the ability to use multi-level layers frees up valuable real-estate on the silicon wafer. Materials include a binary lead chalcogenide (PbTe) for detection upto 3.5 micron wavelength, and ternaries (PbSnTe, PbSeS, PbSeTe) that can detect at longer (upto 6 micron) wavelengths.
Optimization of (i) material properties such as grain size, (ii) electrical properties such as resistivity, mobility and carrier concentration, (iii) optical properties such as responsivity and detectivity, as well as (iv) device design, result in improved photoconductive performance. Photoconductor devices include Resonant Cavity Enhanced (RCE) detector structures that enable an order of magnitude improvement in detectivity, multispectral detectors detect dual IR wavelengths in a single pixel, and MIR detectors integrated with waveguide sensors operating at room temperature. The high index and mid-IR transparency of PbTe is harnessed to create metalenses, with volume manufacturing as a goal.
The path to workforce competency includes being able to discover disruptive applications, build prototypes and finally transition them to high volume manufacturing. A glimpse into the negotiation of this path at AIM Photonics Academy will be provided.
An introduction will be made to AIM Photonics Institute, with its world-class CMOS photonics foundry for 300 mm SOI wafers at SUNY-Poly in Albany, as well as its Test Assembly and Packaging (TAP) services offered at a facility in Rochester, NY.