WAVE-GUIDE EFFECT ON THE IMAGE-FORMATION PROCESS IN NEAR-FIELD PHOTOCURRENT SPECTROSCOPY OF SEMICONDUCTOR-LASER DIODES

Near-field photocurrent spectra of high-power laser diode arrays with different wave-guide characteristics are reported. Subwavelength spati al resolution is achieved by using a near-held fibre probe as the exci tation source. The effect of the laser diode waveguide structure and o f surface recombination processes on the near-field photocurrent image formation is discussed and analysed in terms of a beam propagation mo del. Experiments on laser diodes before and after accelerated ageing d emonstrate the potential of the technique for analysing microscopic de fect formation processes in optoelectronic devices. (C) 1997 by John W iley & Sons, Ltd.