The decrease of fringe effect on mercuric iodide film arrays based on one-step mask method

Polycrystalline α-phase mercuric iodide (α-HgI2) film arrays have been prepared on ITO-coated glass substrates by hot-wall physical vapor deposition (HWPVD) method with the mask of 4 × 4 arrays. Film arrays are prepared based on one-step mask method. It is found that there exist differences between central parts and marginal parts of arrays in two aspects including surface morphology and electrical performance. The size distribution of grains in the edge is not uniform and grain boundaries are not clear, but the size distribution in the centre is consistent in morphology. In the aspect of electrical performance, the lowest leakage current of marginal parts and central parts is 4.95 × 10−8 A and 1.01 × 10−8 A respectively. The phenomenon of fringe effect demonstrates that the former is five times as large as the latter. Polishing method is also applied in order to decrease fringe effect of α-HgI2 film arrays. Signal-noise ratios (SNR) of devices are investigated at room temperature irradiated by 5.5 MeV 241Am source.