Calculated carrier concentration dependence of the thermopower at 300 K of n- and p-type InN using Eq. (1).
(a) Illustration of n-type InN with surface and interface accumulation layers (blue), (b) illustration of p-type InN with p-type bulk (red) and surface/interface inversion layers (blue). The inversion and accumulation layer thicknesses are exaggerated here; in reality the surface layers are on the order of 10 nm thick while the films are on the order of 0.5 to thick.
(a) Measured Seebeck coefficient of Mg-doped InN samples as a function of temperature. SIMS Mg content shown in legend. (b) Measured Seebeck coefficient of Mg-doped InN samples at room temperature as a function of the Mg concentration measured by SIMS.
Mott–Schottky plot (area divided by capacitance, the quantity squared vs voltage, plotted here as potential relative to a standard calomel electrode) showing all of the Mg-doped samples and one undoped sample (GS1690, ) for reference. The curves are each plotted on their own log scale and vertically offset for clarity; the hashes on the right hand side mark the maximum for each curve. Samples with positive (negative) Seebeck coefficients at room temperature are shown in red (black) with open (closed) symbols. The blue dashed line is a guide for the eye.
(a) PL spectra at of the sample with the lowest Mg content, 101107C , for several different laser excitation intensities, vertically offset for clarity. Two peaks are clearly resolved: one associated with band-to-band emission , the other with band-to-acceptor transitions as explained in the text. (b) Peak PL intensity is plotted as a function of pumping laser power. The dashed line in (b) is a linear fit to the data.
Summary of electrical and thermoelectric data for Mg-doped InN at room temperature as measured by SIMS, Hall effect, and thermopower measurements. Sheet electron concentrations are reported since the presence of parallel conducting layers precludes a quantitative measurement of the bulk carrier concentration in some samples.
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