The knowledge to be transferred is the know-how of development and implementation of technology micropatteming of GaAs substrates by wet chemical etching. For the etching experiments detailed knowledge in using photolithography shall be applied. After patterning a suitable procedure of passivation is needed. The applicant has to design the masks, to evaluate the optimum experimental parameters for etching and passivation, to choose the best composition of etchant, capping layer material etc. Furthermore, the detailed knowledge of the applicant how to characterize micropatterned Semiconductor substrates and layers before and after passivation by several microscopy and scanning probe techniques, particularly by scanning electron microscopy and atomic force microscopy in order to determine the aspect ratio, shape of groove, surface roughness, degree and homogeneity of filling of groove etc. Finally, the experience of the applicant in discussion how to apply patterned compound semiconductor substrates in devices, e. g. as active element of sensor arrays shall be used. The purpose of the project is to fabricate and test deep periodical micro pattern on semi-insulating GaAs substrates that are under discussion for application as sensor arrays for detection of high-energy X-rays used for imaging techniques with high spatial resolution as radiography and tomography. The micro pattern is a net of grooves of high aspect ratio (depth <= 100 µm, width <= than 5). These grooves shall reduce the effect of blurring in sensor arrays based on GaAs under discussion for the detection of high-energy X-rays and hence improve the spatial resolution. The project applied for shall make a definite contribution to establish the host institution as center for NDT and sensor development in Saxony.