Technology for Very Long Wavelength Infrared Photon Detectors Based on type-II Superlattices

Photon detectors presently available in the very long wave infrared range (lambda > 15 ¿m) are based on extrinsic silicon and HgCdTe. Due to excessive dark current, the operating temperature of these detectors is below 20K. At present, the most promisingalternative is III-V compound semiconductor superlattices based on arsenides and antimonides, such as type-II InAs/GaSb.It is here proposed to study the feasibility of advanced modeling techniques for type-II InAs/GaSb superlattices for very long wavelength infrared photon detector applications, as tools aimed at guiding the material epitaxial growth in order to achievehigher quality superlattices and subsequently higher performance detector devices. The techniques are based on empirical tight binding model. The growth and characterization of superlattices will be conducted to validate and/or fine tune the models.Photon detectors will also be fabricated and measured, and their characteristics correlated with the models. Upon successful achievement of the proposed work, it is anticipated that higher quality and uniformity type-II InAs/GaSb superlattice infrared material will be available. High performance large area single-element detectors based on this materialsystem, operating beyond 15¿m and at temperatures above 40K, will be demonstrated. This will in turn enhance the prospect of focal plane arrays exhibiting similar operational characteristics for space-based applications, including long range missilethreat warning, pollution monitoring, and astronomy. The developed material technology will also have a far reaching impact on the development of mid to very long wavelength infrared devices, such as uncooled infrared photon detectors and mid-infraredlasers.