The role of space-charge-limited-current conduction in evaluation of the electrical properties of thin Cu2O films

Abstract

Space‐charge‐limited‐current conduction is the dominant charge transport mechanism in electrodeposited films of cuprous oxide; the measurement of current‐voltage characteristic and temperature dependence of conductivity, while charge transport is space‐charge limited, is used to evaluate the electrical parameters of the films. From these measurements and the measurement of the material band gap and dielectric constant, the energy‐band diagram of Cu₂O films has been determined for the first time. An optoelectronic band gap of 2.0 eV and a dielectric constant of 8.8 is measured for these films. The hole mobility in a sample with a resistivity of 1.1×10¹¹ Ω cm is measured to be 8.7 cm²/V s. The conductivity of this sample is controlled by an acceptor‐type deep level (0.54 eV above valence band) with a concentration of 6.65×10¹⁴ cm⁻³ which is compensated with a donor‐type level (0.92 eV below conduction band) having a concentration of 6.64×10¹⁴ cm⁻³.