Peter Feng

Fabrications and application of single crystalline GaN for high-performance deep UV photodetectors

High-quality single crystalline Gallium Nitride (GaN) semiconductor has been synthesized using molecule beam epitaxy (MBE) technique for development of high-performance deep ultraviolet (UV) photodetectors. Thickness of the films was estimated by using surface profile meter and scanning electron microscope. Electronic states and elemental composition of the films were obtained using Raman scattering spectroscopy. The orientation, crystal structure and phase purity of the films were examined using a Siemens x-ray diffractometer radiation. The surface microstructure was studied using high resolution scanning electron microscopy (SEM). Two types of metal pairs: Al-Al, Al-Cu or Cu-Cu were used for interdigital electrodes on GaN film in order to examine the Schottky properties of the GaN based photodetector. The characterizations of the fabricated prototype include the stability, responsivity, response and recovery times. Typical time dependent photoresponsivity by switching different UV light source on and of...

Correction: Nanoscale structure study of boron nitride nanosheets and development of a deep-UV photo-detector

Correction for ‘Nanoscale structure study of boron nitride nanosheets and development of a deep-UV photo-detector’ by Muhammad Sajjad et al., Nanoscale, 2014, 6, 4577–4582.

A compact design of a characterization station for far UV photodetectors

A newly fabricated characterization station is presented. It is a compact, cost-effective, and easily adjustable apparatus. Each part including 4-pin probe, manipulators, operating temperature, and applied bias can be independently controlled. The station can provide highly reliable, reproducible, and economical methods to quickly conduct and complete the characterizations of a large amount of sensing materials within a short period of time. It is particularly suitable for studies of various nanostructured materials and their related thermal effect, polarization effect, sensitivity, and electrical and electronic properties.

Dielectric-barrier discharge plasma source and its application to synthesis of diamond like carbon films

Dielectric barrier discharge plasma sources have been studied and used for syntheses of diamond like carbon thin films. The plasma electrical properties under different gases concentrations and pressures were diagnosed. Based on the results of characterizations, dielectric barrier discharge plasma at different methane-hydrogen-argon gas ratios was used to synthesize large area of diamond like carbon films. Experimental data indicate that only at argon concentration equal to or less than 75% diamond like carbon film fabrication could be accomplished, which has been confirmed based on the Raman spectra and their hardness measurements, whereas high argon content during deposition would result in graphite type of thin films.

Synthesis and Control of Nano-Scale CN Particles and its Distributions

Micro-scale to nano-scale carbon nitride (CN) particles were prepared by using plasma sputtering deposition technique. The preferred orientation of nanoscale CN particle distributions was obtained. Particles have been examined by using both Scanning Electron Microscopy (SEM) and Raman scattering (RS) spectroscopy. Setting bias voltage up to 5 kV, plasma-sputtering deposition gave rise to several ring (diameters: 2.4, 3.2, and 4.4 mm) patterns of particle distributions where many small groups of nanoscale particles were observed. Each group of these particles appeared in a sunflower type of distribution, in which the biggest (85 nm) particle at the center was surrounded by many small sizes (30 nm) of CN particles. Disk type of the particles with a diameter of 10 μm was also observed at different experimental conditions. Typical G, D bands and C=N band in the Raman spectra of the samples were identified. The intensity of the D bands obviously varied at the different deposition conditions.