Exploration of current-voltage (I-V) behaviour of Au/SnO2/n-type InP heterojunction in the temperature range of 200-400

The Au/SnO2/n-InP heterojunction (HJ) diode was fabricated with an e-beam deposited tin oxide (SnO2) film in between the Au and InP substrate as an interlayer and explored its current-voltage characteristics in the temperature range of 200-400 K. The zero-bias barrier height (Phi(B0)) and ideality factor (n) values determined for HJ diode changed from 0.51 eV and 4.32 at 200 K to 0.81 eV and 1.63 at 400 K, respectively. The Phi(B0) increases, while n decreases with increasing the temperature which may be the evidence of the barrier height inhomogeneities at the interface. The deeds of nkTlq versus kTlq plot for HJ diode specified that a combination of thermionic field emission and field emission mechanisms, i.e. the tunnelling mechanism, may be ruled especially at low temperatures. The plots Phi(B0) versus n, Phi(B0)-q/2kT and (n(-1) - 1) - qlkT show linearity, which may be due to the existence of a Gaussian distribution of the barrier height. From Phi(B0)versus q/2kT plot, the mean barrier ((Phi B0) over bar ) and standard deviation (sigma(o)) are estimated as 1.1149 eV and 0.1473 V, respectively. Further, the estimated interface state density (N-SS) for HJ diode decreases with increasing temperature such behaviour is ascribed to molecular restructuring and reordering at the interface with the impact of temperature. At all temperatures, it is noted that the reverse leakage current is ruled by the Poole-Frenkel emission at the low voltage region whereas Schottky emission is dominated at the high voltage region.

Automated summary

The current-voltage characteristics of the Au/SnO2/n-InP heterojunction diode were investigated and it was found that increasing temperature leads to inhomogeneous barrier height and interface restructuring. The study also suggested the coexistence of thermionic field emission and field emission mechanisms at low temperatures, with a Gaussian distribution of barrier height and a decrease in interface state density with increasing temperature.