Nanoscope iva

Field emission scanning electron microscopy (FESEM, Hitachi S-4800) was used to observe the surface morphology of CGH on sapphire substrate, initial stage of GaN buffer layer on CGH/sapphire, and the following un-doped GaN epilayer grown on them, respectively. To understand the growth mechanism of GaN buffer layer, Raman mapping measurements (NT-MDT, Russia) of RBM of CNT and A₁ (LO) mode of GaN from the GaN buffer layer on CGH/sapphire were performed. The surface topography of GaN layer on CGH/sapphire and on sapphire was probed by atomic force microscope (AFM, Digital Instruments, Nanoscope IV A) in tapping mode. Both samples of GaN layer grown with and without CGH were measured by X-ray diffraction (XRD, X'pert-MRD) with scan rate of 2 degree/min from 20 to 80 degree to compare the crystalline quality. Raman spectroscopy (Renishaw) using 514 nm-line of an Ar-ion laser and photoluminescence (PL) with a 325 nm-line of a He-Cd laser were used to examine the crystalline quality and the residual strain of GaN layer grown on sapphire and on CGH/sapphire. Current-Voltage (I-V) and electroluminescence (EL) measurements on the LED chips were carried out using a probe station system.

Surface wettability of the PMAn films through photo-reaction was investigated by water (DI) drop contact angle measurement. PMAn films were illuminated by high intensity UV source for 1, 3, 5, 10 mins. For surface morphology experiments, the polymer films on silicon wafer were illuminated by a high-intensity UV source for 15 min through a 10 μm line pattered photomask. AFM analyses were carried out at room temperature with a Dimension 3100 SPM equipped with Nanoscope IVa devised by Digital Instruments from Santa Barbara, CA. The AFM tip was oscillated at its resonance frequency (75 kHz). Next, the tip was lifted with fixed distance above the sample surface and scanned at that constant height with a voltage applied.

¹H spectrum was determined on a Bruker ARX-300 spectrometer. The average molecular weight of the polymer was characterized by a gel permeation chromatography (GPC) (model: Waters R-401 ALC/GPC) with THF as an eluent and polystyrene standard for calibration. Fluorescence spectra were obtained with a luminescence spectrometer (PerkinElmer, Model LS55) under excitation at 370 nm. The polymer films were illuminated with a UV lamp (Rolence Enterprise, Inc., Taiwan, power: 13.05 mW/cm²), model POWERARC UV 100. The surface wettability was investigated by a water (DI) drop contact angle measurement using Contact Angle Meter-CAM 101 model (KSV Instruments Ltd, FINLAND). AFM analysis was carried out in room temperature with a Dimension 3100 SPM equipped with Nanoscope IVa devised by Digital Instruments from Santa Barbara, CA. The fluorescent patterns such as were imaged under Olympus-BX51 fluorescence microscope with WB – dichroic mirror DM500, excitation filter BP450-480 and barrier filter BA515. The optical MSCs patterns were obtained from Olympus inverted research microscope model IX71. To detect cell patterns more in detail, MSCs were observed with field emission-scanning electron microscope (HITACHI S-800, Tokyo, Japan) and the picture was taken by scanning microscope image analysis system (ESCAN-4000, Bummi Universe, Tokyo, Japan)