Engineering topics

Su, P.

Publications and source records attributed to Su, P..

4 records

DOE OSTI2019

Monolithic on-chip mid-IR methane gas sensor with waveguide-integrated detector

Herein we demonstrate a monolithic waveguide sensor integrated with a detector on-chip for mid-infrared absorption spectroscopic sensing. The optical sensing element comprises a chalcogenide glass spiral waveguide, and the detector is a PbTe photoconductor integrated directly with the chalcogenide waveguide. The limit of detection of the sensor for methane gas was experimentally assessed to be 1% by volume. Further optimization of the fabrication process and normalization of the laser power fluctuations should result in a maximum sensitivity of 330 ppmv.

75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND↗

DOE OSTI2016

On-chip chalcogenide glass waveguide-integrated mid-infrared PbTe detectors

Here, we experimentally demonstrate an on-chip polycrystalline PbTe photoconductive detector integrated with a chalcogenide glass waveguide. The device is monolithically fabricated on silicon, operates at room-temperature, and exhibits a responsivity of 1.0 A/W at wavelengths between 2.1 and 2.5 μm.

36 MATERIALS SCIENCE↗

NASA NTRS1983

Techniques for improving the Si-SiO2 interface characterization

The two techniques which have provided most of the information on interface states in MIS-C (metal-insulator-semiconductor-capacitor) structures are the 'quasi-static method' and the 'conductance method'. Sher et al. (1979) and Su et al. (1980) have suggested a number of improvements concerning these methods. The present investigation has the objective to extend the earlier results and to offer a new tentative interpretation of the data. A critical review is conducted of the data collection and reduction techniques for the quasi-static method, taking into account the sample, the quasi-static capacitance, and the surface potential. In connection with a discussion of the conductance method, attention is given to parallel conductance and capacitance measurements, interface-state densities, time constants, and measurements on a (110) surface orientation.

Sher, A.↗

NASA NTRS1980

Improved characterization of the Si-SiO2 interface

Refined quasi-static and conductance methods, based on effectively thin composite insulating layers, low-carrier-concentration bulk semiconductors, and low-level illumination, have been applied to an improved characterization of the (100) Si-SiO2 interface. Accurate measurement of both the total density of interface states and its major components as a function of energy in the forbidden gap have been made over four decades (10-billion to 100-trillion states/eV sq cm) on a single sample. The normal U-shaped density of states is resolved into separate valence- and conduction-band-derived contributions as well as impurity-derived contributions corresponding to concentrations on the order of 20 ppm at the interface.

Su, P.↗