Lee Hosun

We measure pseudodielectric functions in the visible-deep ultraviolet spectral range of Pb(ZrxTi1−x)O3 (x=0.2,0.56,0.82) (PZT), Pb0.98Nb0.04(Zr0.2Ti0.8)0.96O3, Pb0.91La0.09(Zr0.65Ti0.35)0.98O3, and Pb0.85La0.15Ti0.96O3 films grown on platinized silicon substrates using a sol-gel method and on (0001) sapphire using a radio-frequency sputtering method. Using a parametric optical constant model, we estimate the dielectric functions (ϵ) of the perovskite oxide thin films. Taking the second derivativ

Using spectroscopic ellipsometry and Raman spectroscopy, we measured the pseudodielectric function and the phonon frequencies of fluorinated nanocrystalline carbon (nc-C:F) thin films grown on silicon substrate at varying growth temperature and gas flux ratio of CH4 and CF4. Utilizing the Tauc–Lorentzian formula, we performed multilayer analysis to estimate the dielectric function of the fluorinated nanocrystalline carbon thin films. We also adopted Gaussian-like density-of-states model proposed

We report pseudodielectric function data 〈ε〉=〈ε1〉+i〈ε2〉 of Zn1−xMgxSe and Zn1−xBexSe samples grown on GaAs substrates. The data were obtained from 1.5 to 6.0 eV using spectroscopic ellipsometry. Critical point parameters were obtained by fitting model line shapes to numerically calculated second energy derivatives of 〈ε〉, from which the bowing parameters and spin-orbit-splitting Δ1 of the E1 and E1+Δ1 gaps were obtained. A transfer of oscillator strength from E1+Δ1 to E1 with increasing Mg and B

In this paper, a robust torque control method is proposed for a robot arm which is equipped with joint torque sensor. The proposed controller is used to control the joint torque and make it to be equal with the torque controller reference input torque. A flexible joint robot model will be introduced to model the robot arm system. The disturbance observer scheme is used to reduce the disturbance effects on the system. The PI torque controller is implemented using the characteristics of disturbanc

Abstract Ge 1 − x Te x thin films were grown using thermal coevaporation deposition. The dielectric functions and the phonon modes of amorphous (a‐) and crystalline (c‐) Ge 1 − x Te x films were measured using spectroscopic ellipsometry and Raman spectroscopy in order to investigate electronic and vibrational properties of these alloys. Using the second derivative spectra of the dielectric functions of a‐Ge 1 − x Te x alloys and the standard critical point (SCP) model, we obtained optical transi

We measured pseudodielectric functions in the visible-ultraviolet spectral range of Pb(ZrxTi1−x)O3 (x=0.2, 0.56, 0.82) (PZT) grown on platinized silicon substrate using the sol-gel method and also on (0001) sapphire using radio frequency sputtering method. Using a parametric optical constant model, we estimated the dielectric functions of the PZT thin films. Taking the second derivative of the fitted layer dielectric functions and using the standard critical point model, we determined the parame

The CuPt-type ordering and dopant effects of ${\mathrm{In}}_{0.5}$${\mathrm{Ga}}_{0.5}$P/GaAs epitaxial layers have been studied using spectroscopic ellipsometry and transmission electron microscopy. The degree of ordering was estimated by both transmission electron diffraction and the position of the direct band edge ${E}_{0}$. Conventional line-shape fitting of ${E}_{1}$, ${E}_{1}+{\ensuremath{\Delta}}_{1}$, and ${E}_{0}$ gaps using the second derivative of pseudodielectric functions shows tha

Amorphous gallium/titanium (Ga,Ti) co-doped indium oxide (In2O3) (GTiIO) films present significant potential as transparent conducting electrodes for use in flexible electronic devices. Amorphous GTiIO films were grown on silicon and glass substrates using linear-facing target sputtering and various oxygen flow rates. Transmittance was as high as 80% in the visible range for O2 flow rates of 0.3, 0.7, and 1.0 SCCM. The lowest resistivity was obtained at f(O2) = 0.3 SCCM with 0.47 mΩ cm. Dielectr

The costs of trenchless projects can vary widely with many factors such as the project size, length, depth, location, surface and subsurface conditions, type of application, etc. Although there have been several studies regarding the cost comparison of trenchless with open-cut methods, practical examples of verifying the reasonableness of actual trenchless construction/replacement costs are still needed. In this paper, the cost of an actual pipe bursting project on the campus of Michigan State U