Lead iodide film deposition and characterization

Correlation between growth orientation and growth temperature for bismuth tri‐iodide films

“…The obtained bismuth tri-iodide films have thicknesses in the range 20 to 33 µm, smaller than the suitable values for 99% stopping of X-rays used for medical radiography. Thicknesses are also smaller than previous reported ones for lead iodide [8,9,11,12] and for mercuric iodide [4,5] films. Thinking on the final application, thicker films should be better, but were not yet intended.…”

“…Several materials, such as Se [1], CdTe [2][3], HgI 2 [4][5][6][7], PbI 2 [8][9][10][11][12][13] and BiI 3 [14,15] have been used for growing films intended for direct and digital ionizing radiation imaging, Among them, the heavy metal iodides have resulted to have especial properties. They have high densities and atomic absorption coefficients (which determine that thicknesses of 70-80 µm are enough for 99% of absorption of 20 keV radiation), wide energy band gaps (1.7 -2.5 eV at RT), therefore they give a lower dark current through the detector without any cooling, and a relative low energy necessary for the creation of an electron-hole pair (4 -5 eV), then, they may give a higher signal to noise response [16].…”

“…On the other hand, if attention is paid to the final application, the selected method should permit an easy scale up to large and uniform areas. For this purpose, PVD is suitable as well, and it has been the main method employed for growing mercuric iodide [4][5][6][7] and lead iodide [8][9][10][11][12][13] films. The current success with films of these two last iodides led us to consider bismuth tri-iodide as possible compound semiconductor for X-ray imaging.…”

Stoichiometry, surface and structural characterization of lead iodide thin films

“…According to the present authors knowledge, this method has never been used by any research group in the past for the fabrication of lead iodide (PbI 2 ). Among the many material candidates for the direct detection system, lead iodide is a very promising candidate [7]. The bulk crystalline phase has a melting point at 408 o C, a dielectric constant equal to 21, a mass density of 6.2 g/cm 3 and forbidden band gap of 2.34 eV.…”

"Filmes finos de brometo de tálio (TlBr) produzidos por spray pyrolysis".

“…Por todo o mundo há vários pesquisadores buscando métodos alternativos que possam minimizar o tempo de deposição de filmes semicondutores considerados como bons candidatos a aplicações médicas; como detectores de cintilação, detectores de raios-X em radiografias digitais e tomografia computadorizada, e raios-γ, em Tomografia por Emissão de Pósitron-PET [7], [12][13][14][15]. No processo de fabricação de dispositivos à base de brometo de tálio, geralmente se utiliza cristais crescidos ou pelo método BridgemanStockbarger (BS) ou Travelling Molten Zone (TMZ) [5], [8][9][10], e filmes finos crescidos por evaporação térmica com uma taxa de deposição de 0,2 a 0,3 O crescimento de cristais e/ou filmes finos, utilizando técnicas convencionais é demorado, o que inviabiliza a produção para comercialização em larga escala [19], para tentar solucionar este problema, a produção de filmes a partir da técnica de spray pyrolysis poderia eventualmente se tornar uma boa alternativa, dado que se trata de uma técnica relativamente simples e já utilizada na fabricação de filmes finos de vários outros materiais [20][21][22].…”