Abstract

Near-field light sources utilized in near-field optical techniques microscopes can be used for modification of surfaces in microfabrication, nano-electronics, data recording and other technologies [1-2]. Highly localized electro-magnetic field created by such near-field sources, usually designed as tapered fibers, allows one to minimize the area of action of the radiation on the surface. We present theoretical consideration of the processes induced by near-field excitation of surf aces of semiconductors and metals. The consideration is based on diffusion approach, where thermolisation and recombination of light generated carriers are treated separately. The peculiarity of the excitation is that the size of irradiated zone is less than the free path length of generated carriers. This results in heat release at the larger region compared to the irradiated zone. To take into account the structure of the near-field radiation we used exponential approximation in z-direction and Gaussian approximation in x-y plane. The obtained stationary distribution of temperature and noneqilibrium carriers concentration allows us to estimate the overheat temperature and the size of overheated area. The solution shows that the dimensions of two regions associated to heat release due to thermolisation of nonequilibrium electrons and recombination are essentially different.

© 1996 IEEE