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▼ [20p-A202-16] Plasma and impurity induced surface-modified GaN and its random lasing performance
Keywords:semiconductor, plasma processing, random laser
Different from the conventional laser system, random laser is a relatively new concept of laser in which the feedback amplification is not provided by an external cavity, but by disorder-induced scattering. The disorder structures can be fabricated by lithography-free and self-assembled methods which are relatively simple and cheap. In addition, emissions from the random lasing have low spatial coherence, low-threshold, and high efficiency. With the above features, various applications using random laser have been expected, such as full-field imaging. GaN is one of the promising materials for random lasing due to its high electrical conductivity, and binding energy, especially for the UV-blue light emission. Various GaN random structures, such as nanorods, nanocolumns, and microdisks, have been reported with high lasing performance. However, the fabrication processes which usually contain cleaning, deposition, and temperature control, are complex and time-consuming. Laser processing is a relatively easy way to modify the surface of GaN. Fujiwara et al. exhibited a light emission around 367 nm on the laser pulse treated GaN. However, it is difficult to achieve over a large area due to the small size of the laser beam. Thus, a simple, low-cost, and efficient method is still expected.
In this study, unique structures were formed over a large area by simply irradiating GaN samples in Ar plasma with RF substrate biasing and Mo deposition. Morhology of the modified surface of GaN can be controlled by adjusting the deposition rate of Mo. Moreover, random lasing has been conducted on the plasma-treated GaN by the microspectroscopic system. The relation between features of the light emissions and the surface morphology has been discussed, which indicates the possibility of a controllability of the lasing performance.
In this study, unique structures were formed over a large area by simply irradiating GaN samples in Ar plasma with RF substrate biasing and Mo deposition. Morhology of the modified surface of GaN can be controlled by adjusting the deposition rate of Mo. Moreover, random lasing has been conducted on the plasma-treated GaN by the microspectroscopic system. The relation between features of the light emissions and the surface morphology has been discussed, which indicates the possibility of a controllability of the lasing performance.