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Lasers have the potential for the micromachining of germanium (Ge). However, the thermal damages associated with the laser machining process need to be properly controlled. To minimize the thermal damages, a hybrid laser-waterjet ablation technology has recently been developed for micromachining. This paper presents an experimental study to assess the machining performances in microgrooving of Ge by using a nanosecond laser and the hybrid laser-waterjet technology. The effects of laser pulse energy, pulse overlap and focal plane position on the groove geometry and heat affected zone (HAZ) size are analyzed and discussed. It is shown that the hybrid laser-waterjet technology can give rise to narrow and deep microgrooves with minimum HAZ.

Dye-sensitized solar cell (DSSC) is part of the thin film family that consists of a TiO2 electrode coating which acts as a photo electrode, sensitizer from dye molecules soaked in the TiO2 film, electrolyte layer and a counter electrode. This paper focuses on the usage of a sensitizer from the rose flower and will review some of the research conducted on dye sensitizers from other researcher. Rose flower also known as woody perennial of the genus Rosa, within the family Rosaceae is extracted and were used as sensitizer to fabricate dye sensitized solar cell (DSSC). The photoelectrochemical performance of Rose sensitized solar cell shows parameter of open circuit voltage, VOC,short circuit current, (ISC), fill factor (FF), solar cell efficiency (η), and peak absorbance rate as much as 0.13 V, 57.58 µA, 0.58, 0.85% and 3.5 at 550nm respectively. The photoelectrochemical performance of DSSC and the usage of natural sensitizer from Rose flower dye demonstrate good potential to be applied as a sensitizer yet detail investigations are essential in terms of its applicability for long term application.

Retracted paper: The conventional material for the optical fiber communication laser diode is based on InGaAsP, which might be substituted by a potential candidate, InGaAlN. The new active region material, InN, is introduced regarding to its crystal growth and characterization, including the structural, optical and electrical properties. This material is promising for providing good performance of temperature stability of the wavelength. In addition, it is environmentally friendly.