Electrical Properties of a p–n Heterojunction of Li-Doped NiO and Al-Doped ZnO for Thermoelectrics

Abstract

The electrical properties of a p-n heterojunction of polycrystalline p-type Ni0.98Li0.02O and n-type Zn0.98Al0.02O have been investigated for potential applications in high-temperature oxide-based thermoelectric generators without metallic interconnects. Current-voltage characteristics of the junction were measured in a two-electrode setup in ambient air at 500 -1000 °C. The resistance and rectification of the junction decreased with increasing temperature. A non-ideal Shockley diode model was used to fit the measured current-voltage data in order to extract characteristic parameters of the junction, such as areaspecific series resistance Rs and parallel shunt resistance Rp, non-ideality factor, and the saturation current density. Rs and Rp decreased exponentially with temperature, with activation energies of 0.4 ± 0.1 eV and 1.1 ± 0.2 eV, respectively. The interface resistance of the direct p-n junction studied here is as such too high for practical applications in thermoelectrics. However, it is demonstrated that it can be reduced by order of magnitude by using a composite of the individual materials at the interface, yielding a large effective contact area.

High-Performance μ-Thermoelectric Device Based on Bi2Te3/Sb2Te3 p–n Junctions

“…Figure b shows the replot of the J – V curve in the semilogarithmic mode for the heterojunctions, and the ideality factor is found to be ≈1.1. Since the ideality factor is close to unity, the electrical transport of the junctions is dominated by diffusion current, where recombination processes are minor. , Furthermore, the diode characteristics of the present device are improved when compared with the ones presented by Chavez et al , and Desissa et al in their bulk devices with a p–n junction without metal contact. Particularly, Chavez et al reported an inhomogeneous p–n junction due to the mixing of the nanoparticle powders prior to and during the densification step for the device fabrication.…”