Keywords : Hall phenomena
journal of kerbala university,
Volume 5, Issue 3, Pages 282-291
The a-Ge1-xSbx thin films of (250±20) nm thickness were fabricated according to the weight percentages (x = 0.5, 1, 1.5, 2)%wt, by using the thermal evaporation technique under vacuum (10-6mbar) and (2.7±0.05)Ao/s. The specimens have been exposed to(500rad) -ray. The D.C. electrical measurement were carried out in a range of 0 -3Vol. The effect of -radiation on Hall parameters and optical energy gap were investigated for determining the no. of carriers and controlling on optical energy gap of semiconductors. The examination x-ray diffraction showed that all the films have amorphous nature. There are two activation energies for all films of n-type at (493-305)K that the carriers increase to (41.67 x 1019 cm-3)by increasing the percent to x=2,and they showed a decrease after exposed to radiation to(29.76 x 1019 cm-3) at the same value of x. But the mobility decrease to (0.140 x 10-3 cm2/V.s)by increasing of x to 2 percentage and they are increasing after exposure to - rays with (0.170 x 10-3 cm2/V.s). The optical energy gap is (0.840eV) for a-Ge(unexposed to -rays), but becomes (0.872eV) after exposure , but it is increasing from (0.786eV) to (0.815eV)after exposed to radiation at x=2. This indicates an absorption edge shift towards high energies due to the effect of radiation.