Very Black Infrared Detector from Vertically Aligned Carbon Nanotubes and Electric-Field Poling of Lithium Tantalate

Abstract

Vertically aligned multiwall carbon nanotubes were grown by water-assisted chemical vapor deposition on a large-area lithium tantalate pyroelectric detector. The processing parameters are nominally identical to those by which others have achieved the "world's darkest substance" on a silicon substrate. The pyroelectric detector material, though a good candidate for such a coating, presents additional challenges and outcomes. After coating, a cycle of heating, electric field poling, and cooling was employed to restore the spontaneous polarization perpendicular to the detector electrodes. The detector responsivity is reported along with imaging as well as visible and infrared reflectance measurements of the detector and a silicon witness sample. We find that the detector responsivity is slightly compromised by the heat of processing and the coating properties are substrate dependent. However, it is possible to achieve nearly ideal values of detector reflectance uniformly less than 0.1% from 400 nm to 4 microm and less than 1% from 4 to 14 microm.

A Thin-Film Infrared Absorber using CNT/Nanodiamond Nanocomposite

“…A 150 nm thick silicon nitride layer, a commonly used absorber for microbolometers, was deposited on a glass substrate for comparison. For IR absorber films made from CNTs or carbon/graphite paints, the reflectance ranges from 0 to 5% at most for comparable spectral ranges [19]. Thus similar reflectance is expected for the samples in this work.…”

Scalable Preparation of Broadband Ultrablack Graphite Nanoneedle Surfaces Through Self-Masked Etching

“…Ni-P [4,5], vertically aligned carbon nanotubes [6,7], and noble metals [8] are the most prominent established methods for the production of ultrablack materials. These ultrablack materials have many exciting applications in thermophotovoltaics [9], thermal detectors [10], infrared imaging [11,12] and thermal management [13]. Since room temperature black-body's radiation has a peak around a wavelength of 10-µm, broadband ultrablack material (from VIS to mid-IR) is a good system for radiative heat transfer especially in the outer space where radiative transfer is the only way to dissipate heat.…”

Point defects in ZX-cut Lithium niobate and Lithium tantalate and their influence on acousto-electric properties

“…[1][2][3] Lithium tantalate (LiTaO3, abbreviated as LT) is a perovskite crystal with a similar crystal lattice as Lithium niobate (LN). It has unique piezoelectric and ferroelectric properties with applications in nonlinear optics, 4 infrared sensors, 5 terahertz detectors, 6 cell phones, 7 optical waveguides, 8 SAW substrates, 9 and others. Both LT and LN are grown by the Czochralski method.…”