Transport mechanism in aluminum nitride-metal multilayer junctions

Abstract

The electrical behavior of aluminum nitride ͑AlN͒ thin film structures consisting of alternating AlN and platinum ͑Pt͒ layers has been studied. Typical single layer AlN thin films are insulating due to the wide bandgap properties of the material, but stacked AlN-Pt structures can be conductive. Conductivity studies of the structures indicate regions of semiconductor behavior as well as regions where tunneling occurs. The thickness of the AlN layers, as well as the number of AlN-Pt interfaces in the structures, is found to impact the conduction and tunneling mechanism. Fowler-Nordheim theory and plots were used to determine trends in the electrical behavior and it was found that the field enhancement factor depends on the total thickness of the AlN layers, while the conduction mechanism, tunneling, or multistep hopping between midbandgap states, depends on the number of interfaces as well.

Electrical investigations of AlGaN/AlN structures for LEDs on Si(111)

“…In Ref. 10, for the FN emission in Pt/AlN‐ML structures the following dependence I / E 2 = aΦ −1 β 2 − exp(( bΦ 3/2 / βE )) was used with a and b ‐constants, E – applied field (= V / d , d – LED thickness), Φ – triangular potential barrier height, β – field enhancement factor. Figure 5 shows this dependence for three LED structures.…”

Investigation of structural properties of organic thin films for solar cell and transistor applications

“…F-N theory and the corresponding equation(Eq.8.4) have been used to analyze the I-V results at each applied gate bias. J is the field emission current; φ is the work function; E = βV represents the applied electric field; and β is the field enhancement factor which is defined as the ratio of the local surface electric field to the applied bias[99].…”

“…Since all of the I-V data for this work is taken in the range of -40 to 40 V for drain-source voltages, the transition in the charge carrier for forward biases cannot be presented in the corresponding F-N plots.The dependency of the field enhancement factor and the work function on the applied gate bias was shown by calculating the slopes of the tunneling region. The value of β is related to the geometry, crystal structure, surface morphology and electrical homogeneity[100,101].Although tunneling current is known to be affected by the field enhancement factor as well as the work function, as the effects of these two parameters are coupled together, it is difficult to analyze the F-N current based solely on one or the other[99]. The drain-source voltage at which the conduction mechanism switches from hopping to tunneling was extracted for each of the gate biases by calculating the slopes of the hopping and the tunneling regions in the F-N plots.…”