Near single-crystal electrical properties of polycrystalline HgI/sub 2/ produced by physical vapor deposition

Polycrystalline films of HgI/sub 2/ prepared by physical vapor deposition (PVD) were found to have electrical charge transport properties similar to those of single crystals. Transient charge transport (TCT) measurements were used to evaluate the electrical conduction properties of the samples. The mobility (mu), trapping time (tau), and surface recombination velocity s of electrons or holes were determined by analyses of transient voltages developed across the sample in response to a drift of the corresponding charge carriers created by alpha particle absorption near one of the electrodes. Typical electron and hole mobilities were (mu)/sub n/=88 cm/sup 2//V.s and (mu)/sub p/=4.1 cm/sup 2//V.s, respectively; trapping times were (tau)/sub n/>16 (mu)s and (tau)/sub p/<3.5 (mu)s, and surface recombination velocities s/sub n/=1.4*10/sup 5/ cm/s and s/sub p/=3.7*10/sup 3/ cm/s. All parameters depend to a large extent on the material deposition technology. The effect of carriers being first generated in nearsurface traps and then gradually released is observed.