A multilayer structure is described for use in a number of radiation detectors. The structure consists of alternating layers of metal and amorphous silicon (a-Si). The absorption of radiation mainly occurs in the metal layers, while electron-hole pairs are generated in the a-Si layers by the emitted secondary particles from the metal layers. The fundamental applicability of this novel detector for X-ray detection was confirmed by Monte Carlo computer simulations as well as by results for an experimental five-layer Ta(0.5 mu m)/a-Si(3 mu m)/Mo(0.5 mu m) X-ray sensor fabricated on a 1.5-cm*4-cm glass plate. The authors have confirmed that the detector has rectifying characteristics, with the Mo and Ta layers forming Schottky barrier and ohmic contacts respectively. >