Study On Electrical Property And Phase Transition Of InSb Under High Pressure

Because InSb has narrower energy band gap, higher electron mobility and smaller effective electron mass, it possesses a good prospect of application in the fields of infrared detector, large-scale infrared focal plane array CCD and magnetic-sensing device. In this thesis, we did some detailed research in the aspect of electrical transport property, phase transition and photoconductivity of InSb under high pressure.1. With a microcircuit integrated diamond anvil cell, we studied the electrical transport property of InSb under high pressure by in situ measuring its pressure dependence of electrical resistivity, and obtained results as follow: (1) At 3.2 GPa, an abnormal resistivity change was found to have relations with the phase transition of InSb from initial cubic Zinc-blende P1 (InSb-â… ) phase to orthorhombic P₄ (InSb-â…£) phase. It was identical with the report"3 GPa"of literature; (2) The abnormal resistivity change in pressure range of 5 GPa to 6 GPa was related to the phase transition from P₄ (InSb-â…£) phase to P₅ (InSb-â…¤) phase. It was slightly different from the phase transition point-6.3 GPa which was reported by the literature, maybe caused by the quasi- hydrostatic pressure effect; (3) At approximate 10 GPa, a slight increase of resistivity-pressure curve was found, which indicated the phase transition from P₅ (InSb-â…¤) phase to InSb-â…¢phase.2. By using high pressure X-ray synchrotron radiation technique, we investigated the phase transition behavior of InSb under high pressure. It can be seen from the diffraction data that: (1) at 3.16 GPa, three new diffraction peaks emerged in the spectrum that correspond to the crystallographic planes (200), (101), (211) of P₄ (InSb-â…£) phase, and the crystallographic planes (111), (311), (400) and (331) of P1 (InSb-â… ) phase disappeared, which indicates the structural phase transition of InSb from P1 (InSb-â… ) phase to P₄ (InSb-â…£) phase; (2) at 6.68 GPa, the crystallographic plane (220) of P₄ (InSb-â…£) phase disappeared, indicating the structural phase transition from P4 (InSb-â…£) phase to P5 (InSb-â…¤); (3) after 12.64 GPa, the crystallographic plane (201) of InSb-III phase appeared in the spectrum.3. We applied the module of CASTEP in Materials Studio to the theoretical calculation of energy band structure of InSb. At 2.5 GPa, the band gap width of P3 (InSb-â…¢) phase is 0.0024 eV. At 5 GPa, the band gap width of P4 (InSb-â…£) is 0.0053 eV. , they were all narrow band-gap semiconductors. In the measurement of photoconduction of InSb at ambient temperature, it was found that within the pressure range of 1.8 GPa the photoconduction phenomena can be seen. However, with the increase of pressure over 1.8GPa, the phenomena of photoconduction was not obvious.In conclusion, we studied the electrical transport property of InSb powder with the microcircuit integrated diamond anvil cell ,by in situ measuring its pressure dependence of electrical resistivity, the sequence phase transition of P1→P4→P5→InSb-III was detected.. The result was consistent with that of high pressure X-ray synchrotron diffraction. With the module CASTEP, we calculated the energy band structure of InSb with 5 GPa, and found that within this pressure range InSb is narrow band gap semiconductor. Meanwhile, we also studied the photoconduction of InSb under high pressure.