Charge transport mechanism in thin cuticles holding nandi flame seeds.
Metal-sample-metal sandwich configuration has been used to investigate DC conductivity in 4 mum thick Nandi flame [Spathodea campanulata P. Beauv.] seed cuticles. J-V characteristics showed ohmic conduction at low fields and space charge limited current at high fields. Charge mobility in ohmic region was 4.06 x 10(-5) (m(2)V(-1)s(-1)). Temperature-dependent conductivity measurements have been carried out in the temperature range 320 K < T > 450 K. Activation energy within a temperature of 320 K-440 K was about 0.86 eV. Variable range hopping (VRH) is the main current transport mechanism at the range of 330-440 K. The VRH mechanism was analyzed based on Mott theory and the Mott parameters: density of localized states near the Fermi-level N(E(F)) approximately 9.04 x 10(19) (eV(-1)cm(-3)) and hopping distance R approximately 1.44 x 10(-7) cm, while the hopping energy (W) was in the range of 0.72 eV-0.98 eV.
Physics Department, Kenyatta University, P.O. Box 43844-00100, Nairobi, Kenya.
Wycliffe K
WK
Kipnusu
Gabriel
G
Katana
Charles M
CM
Migwi
I V S
IV
Rathore
Joshua R
JR
Sangoro