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Chemical Visualization of a GaN p-n junction by XPS.

Caliskan D, Sezen H, Ozbay E, Suzer S - Sci Rep (2015)

Bottom Line: Areal maps of the peak positions under reverse bias are completely decoupled with respect to doped regions and allow a novel chemical visualization of the p-n junction in a 2-D fashion.Other electrical properties of the device, such as leakage current, resistivity of the domains are also tapped via recording line-scan spectra.Application of a triangular voltage excitation enables probing photoresponse of the device.

View Article: PubMed Central - PubMed

Affiliation: Nanotechnology Research Center, Department of Electrical and Electronics Engineering and Department of Physics, Bilkent University, 06800, Ankara, Turkey.

ABSTRACT
We report on an operando XPS investigation of a GaN diode, by recording the Ga2p3/2 peak position under both forward and reverse bias. Areal maps of the peak positions under reverse bias are completely decoupled with respect to doped regions and allow a novel chemical visualization of the p-n junction in a 2-D fashion. Other electrical properties of the device, such as leakage current, resistivity of the domains are also tapped via recording line-scan spectra. Application of a triangular voltage excitation enables probing photoresponse of the device.

No MeSH data available.


Related in: MedlinePlus

XPS Intensity Maps.Areal maps of the intensity of the Au4f7/2 and Ga2p3/2 peaks derived from peak areas.
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f2: XPS Intensity Maps.Areal maps of the intensity of the Au4f7/2 and Ga2p3/2 peaks derived from peak areas.

Mentions: Figure 2 displays areal intensity maps of the Au4f7.2 and the Ga2p3/2 peaks recorded in the snap-shot mode. The intensity variations of the Ga peak between various regions are indistinguishable except at the intersection of the un-GaN and the p-GaN regions. In Fig. 3, the areal map of the measured binding energy positions of the Ga2p3/2 peak under +2 V reverse bias is displayed, where now the differences are transformed into the voltage space and amplified. As shown in the inset, the two doped regions display 2.4 eV difference in the binding energy position under +2 V reverse bias, traversing across the gold electrodes. Traversing in the middle and perpendicularly crosses the side-walls of the intersection of the un-GaN and the grounded p-GaN twice. Interestingly although an equivalent of the full junction potential of 2.4 eV is measurable at the side-walls of the un- and p- intersection (see Fig. 3b), only 0.6 eV voltage drop is measured between the un- and the floating p- regions of the neighboring diode (Fig. 3c), indicative of a certain cross-talk among the diodes. Unfortunately, our spatial resolution of >50 μm does not permit assessing the depletion length or other similar properties of the junction45, except for stating that the depletion length is smaller than 50 μm. Note also that the measured binding energy difference in the Au4f7.2 peak of the two gold electrodes is still consistently 2.0 eV, as is also indicated in the inset, and we reiterate that each GaN region and their interfaces exhibit different binding energy shifts.


Chemical Visualization of a GaN p-n junction by XPS.

Caliskan D, Sezen H, Ozbay E, Suzer S - Sci Rep (2015)

XPS Intensity Maps.Areal maps of the intensity of the Au4f7/2 and Ga2p3/2 peaks derived from peak areas.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4566124&req=5

f2: XPS Intensity Maps.Areal maps of the intensity of the Au4f7/2 and Ga2p3/2 peaks derived from peak areas.
Mentions: Figure 2 displays areal intensity maps of the Au4f7.2 and the Ga2p3/2 peaks recorded in the snap-shot mode. The intensity variations of the Ga peak between various regions are indistinguishable except at the intersection of the un-GaN and the p-GaN regions. In Fig. 3, the areal map of the measured binding energy positions of the Ga2p3/2 peak under +2 V reverse bias is displayed, where now the differences are transformed into the voltage space and amplified. As shown in the inset, the two doped regions display 2.4 eV difference in the binding energy position under +2 V reverse bias, traversing across the gold electrodes. Traversing in the middle and perpendicularly crosses the side-walls of the intersection of the un-GaN and the grounded p-GaN twice. Interestingly although an equivalent of the full junction potential of 2.4 eV is measurable at the side-walls of the un- and p- intersection (see Fig. 3b), only 0.6 eV voltage drop is measured between the un- and the floating p- regions of the neighboring diode (Fig. 3c), indicative of a certain cross-talk among the diodes. Unfortunately, our spatial resolution of >50 μm does not permit assessing the depletion length or other similar properties of the junction45, except for stating that the depletion length is smaller than 50 μm. Note also that the measured binding energy difference in the Au4f7.2 peak of the two gold electrodes is still consistently 2.0 eV, as is also indicated in the inset, and we reiterate that each GaN region and their interfaces exhibit different binding energy shifts.

Bottom Line: Areal maps of the peak positions under reverse bias are completely decoupled with respect to doped regions and allow a novel chemical visualization of the p-n junction in a 2-D fashion.Other electrical properties of the device, such as leakage current, resistivity of the domains are also tapped via recording line-scan spectra.Application of a triangular voltage excitation enables probing photoresponse of the device.

View Article: PubMed Central - PubMed

Affiliation: Nanotechnology Research Center, Department of Electrical and Electronics Engineering and Department of Physics, Bilkent University, 06800, Ankara, Turkey.

ABSTRACT
We report on an operando XPS investigation of a GaN diode, by recording the Ga2p3/2 peak position under both forward and reverse bias. Areal maps of the peak positions under reverse bias are completely decoupled with respect to doped regions and allow a novel chemical visualization of the p-n junction in a 2-D fashion. Other electrical properties of the device, such as leakage current, resistivity of the domains are also tapped via recording line-scan spectra. Application of a triangular voltage excitation enables probing photoresponse of the device.

No MeSH data available.


Related in: MedlinePlus