کد مقاله | کد نشریه | سال انتشار | مقاله انگلیسی | نسخه تمام متن |
---|---|---|---|---|
5435495 | 1509352 | 2017 | 8 صفحه PDF | دانلود رایگان |
- The XRD diffraction patterns confirm the polycrystalline phase.
- All azo derivatives (HLn) have semiconductor behavior.
- The operating dc conduction mechanism is the VRH for all samples.
- Both of the ac conduction mechanisms SPT and QMT are observed.
- The variation of substituent group strongly affects the value of Eg.
The electrical and optical absorption properties of 5-amino â2-(aryldiazenyl) phenol (HLn) was investigated. A semiconductor behavior with two thermal activation energies for dc conduction which are in the range 0.11-0.47 eV for ÎE1 at the lower region of temperature and 0.77-1.12 eV for ÎE2 at higher region of temperature are observed. The ac conductivity measurement showed a dependence of Ïac on test frequency following the relations ÏacâÏS. Temperature dependence of the exponent S recommends different conduction mechanisms depends on the chemical structure. The recommended mechanism are small polaron tunneling (SPT) and quantum-mechanical tunneling mechanism (QMT). The optical absorption investigations for HLn thin films show that the ligands HL1 and HL2 experiences indirect optical transition with energy gap 2.02 and 1.89 eV, respectively. The ligands HL3 and HL4 experiences direct optical energy gap with values 2.6 and 2.20 eV, respectively.
Journal: Synthetic Metals - Volume 226, April 2017, Pages 207-214