The aim of the project is to investigate the little understood phenomenom of charge sharing and quality determination of composite semiconductor detectors including both simple diodes and segmented strip and pixel detector structures. The detectors will be provided in frame of the RD50 and Medipix CERN projects. The proposed project will be realised through systematic composite tests of semiconductor detectors. Important tasks are the observation of the spectrometric signal from two electrodes, the measurement of current signals determining the time characteristic of charge collection, narrow beam sample scanning and DLTS measurements of single pixel elements (segments). For the tests, monochromatic radiation sources (alpha, gamma, X-ray) will be available. The proposed project seeks to establish the correlations between the determined inhommogenities in detection efficiency and the inhommogenities in the material, in admixtures and in the contact quality. It is expected that narrow beam scanning of samples and DLTS measurements for individual pixels provide, in the case of pixel sample with determined material inhommogenity, information to establish the main causes of unsatisfactory results in detector fabrication. The results of the experiments focused on the study of charge sharing will be compared with numerical calculations simulating charge motion in semiconductors. Further, techniques of coincidence spectrometry will be used on two neighboring structures to enable the study of lateral and longitudinal charge diffusion.