The influence of annealing temperature and tellurium (Te) on electrical and dielectrical properties of Al/p-CIGSeTe/Mo Schottky diodes

摘要

p-CuIn_(0.7)Ga_(0.3)(Se_((1-x))Te_x) _2 type thin films were synthesized by thermal evaporation method on Mo coated glass substrates. To obtain Al/CuIn_(0.7)Ga _(0.3)(Se_((1-x))Te_x)_2/Mo Schottky diode structure for two compositions of x = 0.0 and 0.6, Al metal was evaporated on upper surface of CuIn_(0.7)Ga_(0.3)(Se_((1-x))Te _x)_2 as a front contact. Al/p-CuIn_(0.7)Ga _(0.3)(Se_((1-x))Te_x)_2/Mo structures were annealed temperature range from 150 C to 300 C for 10 min under vacuum. The electrical and dielectrical properties of Al/p-CuIn_(0.7)Ga _(0.3)(Se_((1-x))Te_x)_2 (CIGSeTe) Schottky barrier diodes (SBD) have been investigated. Capacitance-Voltage (C-V) characteristics, Conductance-Voltage (G/w-V) characteristics and interface state density were studied in order to obtain electrical and dielectrical parameters. The effects of interface state density (Nss), series resistance (Rs), the dielectric constant (é′), dielectric loss (é″), dielectric loss tangent (tan δ), ac electrical conductivity (σac) and carrier doping densities were calculated from the C-V and G/w-V measurements and plotted as a function of annealing temperature. It was observed that the values of carrier doping density N A for annealing temperature at 150 C decreased from 2.83 × 10+15 cm-3 to 2.87 × 10+14 cm -3 with increasing Te content from x = 0.0 to 0.6. The series resistance for x = 0.0 found to be between 10 and 75 Ω and between 50 and 230 Ω for x = 0.6 in the range of annealing temperature at 150-300 °C.