Type Of IR Detector Research Articles

Development of Infrared Detectors Using Single Carbon-Nanotube-Based Field-Effect Transistors

Carbon nanotube is a promising material to fabricate high-performance nanoscale-optoelectronic devices owing to its unique 1-D structure. In particular, different types of carbon-nanotube-infrared detectors have been developed. However, most previous reported carbon-nanotube-IR detectors showed poor device characteristics due to limited understanding of their working principles. In this paper, three types of IR detectors were fabricated using carbon-nanotube field effect transistors (CNTFETs) to investigate their performance: 1) symmetric Au-CNT-Au CNTFET IR detector; 2) symmetric Ag-CNT-Ag CNTFET IR detector; and 3) asymmetric Ag-CNT-Au CNTFET IR detector. The theoretical analyses and experimental results have shown that the IR detector using an individual single-wall carbon nanotube (SWCNT), with asymmetric Ag-CNT-Au CNTFET structure, can suppress dark current and increase photocurrent by electrostatic doping. As a result, an open-circuit voltage of 0.45 V under IR illumination was generated, which is the highest value reported to date for an individual SWCNT-based photodetector. The results reported in this paper have demonstrated that the CNTFET can be used to develop high-performance IR sensors.

QUANTUM STRUCTURES FOR FAR-INFRARED DETECTION

FIR photon detector development starting from the extrinsic detectors for LWIR to FIR wavelengths are presented. Several other types of IR detectors, including the cut-off wavelength extension into the FIR range for quantum well infrared photodetectors (QWIPs), are summarized. Efforts in developing p-GaAs homojunction interfacial workfunction internal photoemission (HIWIP) far-infrared detectors and the most reason developments on GaAs/AlGaAs Heterojunction interfacial workfunction internal photoemission (HEIWIP) far-infrared detectors are presented.

Application of Pyroelectric Sensor and IR-Chopper with Ferroelectric Liquid Crystal for Human Detection.

Infrared chopper elements have been fabricated, utilizing the transient light scattering effect of ferroelectric liquid crystal with asymmetric waveform voltage drive. New elements can performed 12% of modulation degrees in around 10 microns region. A combination of an IR-chopper and a pyroelectric sensor is used to measure radiation intensity from black body at various temperatures to detect human body stationary. The new type of IR detector allows a pyroelectric sensor array easily to be developed to measure temperature distribution over large area. The detection has achieved 0.55°C noise equivalent temperature difference (NETD).

Specimen Size Effect of the Thermal Diffusivity/Conductivity of Aluminum Nitride

It has been generally found that the thermal diffusivity/conductivity of AIN measured by the laser‐flash technique decreases with decreasing specimen size. The results of this study indicate that much of this effect can be attributed to the relatively large temperature rises for thin specimens, especially for high‐energy laser pulses, and results from the combination of the noninearity of the commonly used type of IR detector and the strongly negative temperature dependence of the thermal diffusivity of AIN. The experimental results indicate that for reliable data, the specimen temperature rise at thermal equilirium should be kept to less than 1°C by using specimens with a thickness near 3 mm in combination with keeping the pulse energy to a reasonable minimum by attenuation of the laser beam by passing it through an aqueous solution of CuSO4.

Detection of Low Contrast Targets at 5 μm and 10 μm: a Comparison

The purpose of this experimental study is to compare the performance of two types of ir detectors for detection of distant ships against a sea or horizon background. The detectors are of the InSb and Hg(1-x) Cd(x)Te types, sensitive in the 5-microm and 10-microm region, respectively. The results obtained from radiometric measurements seem to confirm theoretical estimates that the Hg(1-x)Cd(x)Te detector is superior for this task compared to the InSb detector.