Oriented polycrystalline α-HgI2 thick films grown by physical vapor deposition

Growth of oriented polycrystalline α-HgI2 films by ultrasonic-wave-assisted physical vapor deposition

“…Compared with type d film obtained at 80 1C without ultrasonic wave, for type h and l films, fully oriented (0 0 1) peaks are observed, indicating uniformly oriented polycrystalline a-HgI 2 film can be obtained with the assistance of ultrasonic wave. Due to the inherent layer structure of the tetragonal red phase of a-HgI 2 crystal, the aggregated HgI 2 molecules tend to align themselves with c-axis parallels to the growth direction if the surface diffusion energy is high enough [5]. As a result, the crystallographic orientation of the film and texture can be improved by using ultrasonic wave.…”

“…Mercuric iodide is one of the most suitable semiconductor materials for gamma ray and X-ray detectors operating at room temperature because of its favorable characteristics such as high atomic number of its constituent elements and large band gap (2.13 eV), resulting in a high photopeak efficiency [1][2][3][4][5]. Though detector properties of polycrystalline HgI 2 are not yet comparable to that of single crystal HgI 2 , polycrystalline films of HgI 2 are of renewed interest to be used as one of the promising direct converters in X-ray digital radiography because of the lower fabrication cost for large area detectors and practical experience gained with HgI 2 material in space and commercial applications [6][7][8].…”

“…The better the orientation, the better the charge transport along c-axis of microcrystals when they are irradiated. Oriented polycrystalline a-HgI 2 films have been grown through varying the growing conditions of PVD [5,10,11].…”

Simulation and characterization of polycrystalline mercuric iodide film detector based on coplanar grid electrode

“…C.T. Shih and coworkers [21] presented that due to the inherent layer structure of the tetragonal phase HgI 2 crystal, the aggregated HgI 2 molecules tend to align themselves with c-axis parallels to the (001)-oriented growth direction if the surface diffusion energy is high enough. Based on the above XRD result, it shows that the crystal structure of HgI 2 film grown along (001)-oriented direction belongs to the tetragonal system.…”

Coplanar-grid electrode design of HgI2 detector by finite elements simulation

“…Single-crystal HgI 2 detectors have demonstrated excellent energy resolution and detection efficiency, and the performance of polycrystalline film has been approaching that of single-crystal over the last few years [8][9][10]. Because of the lower fabrication cost for large area detectors and the more practical experiences gained with HgI 2 materials in space and commercial applications, polycrystalline α-HgI 2 films are thought to be one of the promising direct converters in X-ray digital radiography [11][12][13][14][15][16].…”