Transmission and Reflection Measurements

Raman scattering was often applied for studying the phonon modes of ZnO bulk samples [31-38], It has become a fast and reliable tool to study ZnO thin films [29,38-43], and ZnO nano- and/or microstructures [44-46]. Raman scattering studies were also reported for ZnO samples doped with Li [43, 47, 48], N [43, 49-51], A1 [48, 52-54], P [43, 55], Mn [43, 56-58], Fe [43, 48], Co [43], Ni [43], Cu [43], Ga [48, 51], As [59], Ce [60], or Sb [48, 61], and (Mg,Cd)xZni a 0 [43, 62] samples. IR reflection [63-65] and transmission measurements [66-68] were reported mainly for ZnO bulk materials. IR optical studies of doped ZnO and ZnO-based thin films are, in general, restricted to transmission and reflection measurements in the near-IR (NIR) spectral region, and to highly conductive Al-doped ZnO thin films. Some experiments were performed in the mid-IR (MIR) spectral region [52,69,70], where the optical phonon modes can be studied. Recently, IRSE was applied to study undoped and doped ZnO films, and ZnO-based alloy films [30,38,43,62,71-74]. 

The number of spectroscopic studies of ZnO and related materials in the spectral region around the fundamental band gap is too large to be listed here. Undoped and doped ZnO as well as ZnO-based alloy samples were studied by photoluminescence (PL), transmission and reflection measurements (see review articles [6,75]). Also, SE measurements were reported for ZnO [76-85] and related materials, for instance, metal-doped ZnO [70,86-89], Mg, Zni ,() [15,16,82,90,91], Co.Zm O [92], Mn.Zm O [93], or Fe Zm O [94],... 

Fig. 10 Immobilized AuNPs on the end fire of an optical fiber for transmission and reflection measurements...

For transmission and reflection measurements, a 15x objective with a numerical aperture (NA) of 0.4 and an imaging area or field of view (FOV) of 260 x 260 pm ... 

The imaging area for transmission and reflection measurements is consistent with the detector size (3.9 x 3.9mm ). For ATR-measurements, the imaging area is 3.9 X 5.5 mm because of the illumination geometry [37]. 

The spectrometer can also incorporate facilities for single beam transmission and reflectance measurements since it is often necessary to determine the amount of light reflected or absorbed in order to calculate the quantum efficiency of photocurrent generation. Optically transparent electrodes (OTEs) are particularly useful substrates since they allow simultaneous measurements of photocurrents and transmission to be made. Metal films can be prepared by vacuum deposition on the OTEs or, in some cases, the material of interest can be electroplated directly. If Sn02-coated quartz electrodes are used, it is essential to check them periodically to make sure that they do not give rise to background photocurrents since aged electrodes... 

J. Kuhn, S. Korder, M. C. Arduini-Schuster, R. Caps, and J. Fricke, Infrared-Optical Transmission and Reflection Measurements on Loose Powders, Rev. 

In infrared emission spectrometry, very weak infrared radiation of emission from a sample itself is to be measured. Consequently, infrared emission measurements have requirements considerably different from transmission and reflection measurements. It is not desirable to use a complicated optical apparatus for emission measurements. 

Figure 16.1 Schematic of an infrared microscope set-up that can be used for both transmission and reflection measurements. (Source Adapted with permission from the catalog of Bruker Optics, Inc.)...

Transmission and reflection spectra of the boron films on sapphire were measured over a wavelength range 200-2500 pm using an MPS-50 (Shimazu) spectrophotometer. In the transmission and reflection measurements, an uncoated sapphire and an evaporated aluminum film were used as the references, respectively. Absorption coefficient, refractive index, and extinction coefficient of the boron films were calculated from the measured transmittance and reflectance at normal incidence. 

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