High-temperature Schottky diode characteristics of bulk ZnO

Abstract

Current–voltage (I–V) measurements of Ag/n-ZnO have been carried out at temperatures of 200–500 K in order to understand the temperature dependence of the diode characteristics. Forward-bias I–V analysis results in a Schottky barrier height of 0.82 eV and an ideality factor of 1.55 at room temperature. The barrier height of 0.74 eV and Richardson constant of 0.248 A K−2 cm−2 were also calculated from the Richardson plot, which shows nearly linear characteristics in the temperature range 240–440 K. From the nkbT/q versus kbT/q graph, where n is ideality factor, kb the Boltzmann constant, T the temperature and q the electronic charge we deduce that thermionic field emission (TFE) is dominant in the charge transport mechanism. At higher sample temperatures (>440 K), a trap-assisted tunnelling mechanism is proposed due to the existence of a deep donor situated at Ec—0.62 eV with 3.3 × 10−15 cm2 capture cross section observed by both deep-level transient spectroscopy (DLTS) and lnI0 versus 1/kbT plots. The ideality factor almost remains constant in the temperature range 240–400 K, which shows the stability of the Schottky contact in this temperature range.

Temperature-dependent current–voltage characteristics of Pd/ZnO Schottky barrier diodes and the determination of the Richardson constant

“…and searchers [2,17,20,22,23]. The difference in the calculated values of the Richardson constant for different temperature ranges can be attributed to inhomogeneity in the barrier.…”

“…It has a larger exciton binding energy of 60 meV and hence a high efficiency in excitonic emission [1,2]. In addition, it has superior electronic properties such as high breakdown voltage, high electron saturation velocity, high thermal conductivity and is very resistant to high-energy radiation, making it a very suitable candidate for applications in space and around nuclear reactors [3,4].…”

The effect of high temperatures on the electrical characteristics of Au/n-GaAs Schottky diodes

“…Örzeli et al [12] explained the temperature dependence of the I-V and C-V characteristics at high temperatures (280 -415 K) of Au/n-GaAs Schottky diodes using a Gaussian distribution of the Schottky barrier height. Similar experiments have been undertaken with samples exposed to and measured at the same high temperatures in other materials [15,16]. It is also important to take note of any changes and modifications as they occur when the device is exposed to high temperatures during measurement or operation since diode electrical characteristics are sensitive to heat treatment [17].…”

Analysis of temperature-dependant current–voltage characteristics and extraction of series resistance in Pd/ZnO Schottky barrier diodes

“…The investigation of the forward bias I-V characteristics in a wide temperature range gives a clear understanding of the aspects of the current transport mechanism and the barrier formation. In general, the forward bias I-V characteristics of these devices deviate from the ideal TE theory [6]. There is still some difficulty in predicting the exact transport phenomenon.…”