AlGaN/GaN high electron mobility transistors were irradiated with 60Co gamma-rays to doses up to 1000 Gy, in order to analyze the effects of irradiation on the devices' transport properties. Temperature-dependent electron beam-induced current measurements, conducted on the devices before and after exposure to gamma-irradiation, allowed for the obtaining of activation energies related to radiation-induced defects due to nitrogen vacancies. DC current-voltage measurements were also conducted on the transistors to assess the impact of gamma-irradiation on transfer, gate, and drain characteristics.

An electrically pumped ZnO homojunction random laser diode based on nitrogen‐doped p‐type ZnO nanowires is reported. Nitrogen‐doped ZnO nanowires are grown on a ZnO thin film on a silicon substrate by chemical vapor deposition without using any metal catalyst. The p‐type behavior is studied by output characteristics and transfer characteristic of the nanowire back‐gated field‐effect transistor, as well as low‐temperature photoluminescence. The formation of the p–n junction is confirmed by the current–voltage characteristic and electron beam‐induced current. The nanowire/thin‐film p–n junction acts as random laser diode. The random lasing behavior is demonstrated by using both optical pumping and electrical pumping, with thresholds of 300 kW/cm2 and 40 mA, respectively. The angle‐dependant electroluminescence of the device further proves the random lasing mechanism. An output power of 70 nW is measured at a drive current of 70 mA.

Optical materials capable of advanced functionality in the infrared will enable optical designs that can offer lightweight or small footprint solutions in both planar and bulk optical systems. The University of Central Florida's Glass Processing and Characterization Laboratory, together with our collaborators, have been evaluating compositional design and processing protocols for both bulk and film strategies employing multicomponent chalcogenide glasses (ChGs). These materials can be processed with broad compositional flexibility that allows tailoring of their transmission window, physical and optical properties, which allows them to be engineered for compatibility with other homogeneous amorphous or crystalline optical components. We review progress in forming ChG-based gradient refractive index (GRIN) materials from diverse processing methodologies, including solution-derived ChG layers, poled ChGs with gradient compositional and surface reactivity behavior, nanocomposite bulk ChGs and glass ceramics, and metalens structures realized through multiphoton lithography. We discussed current design and metrology tools that lend critical information to material design efforts to realize next-generation IR GRIN media for bulk or film applications.

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This work reports the processing and properties of a new chalcogenide glass film that can be photo-patterned by multiphoton lithography (MPL) with enhanced post-fabrication stability. Thermally evaporated germanium-doped arsenic selenide [Ge 5 (As 2 Se 3) 95 ] thin films were photo-patterned using the output of a mode-locked titanium:sapphire laser. The morphology, chemical structure, and optical properties of the material were studied before and after photo-patterning and compared for their long-term aging behavior and stability to previously investigated arsenic trisulfide (As 2 S 3) films fabricated using similar MPL conditions. Relative to As 2 S 3 , thermally deposited Ge 5 (As 2 Se 3) 95 is found to offer higher photosensitivity and greater chemical stability after photo-patterning, as evidenced by lack of ageinduced crystallization and reduced feature degradation over a four year aging period. These findings demonstrate the suitability of a new photo-patternable material for the creation of robust, long-lived functional infrared anti-reflective coatings and meta-optics.

P-n junctions based on physical vapor deposition of thin PbSe films and conductivity type inversion from n-to p-type are developed and characterized over a wide range of temperatures and bias voltages. Photosensitivity and diode characteristics in the thin film PbSe diode structures were found at temperatures up to 300 K. The values of the measured and estimated parameters of these structures demonstrate their high photodetector performance and the potential for development of IR detectors with optimal sensitivity at the highest possible operating temperature.

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