Electronic transport characterization of AlGaN∕GaN heterostructures using quantitative mobility spectrum analysis

Abstract

Resistivity and Hall effect measurements in nominally undoped Al 0.25 Ga 0.75 N / GaN heterostructures grown on sapphire substrate by metal-organic chemical vapor deposition are carried out as a function of temperature ͑20-350 K͒ and magnetic field ͑0-1.5 T͒. The measurement results are analyzed using the quantitative mobility spectrum analysis techniques. It is found that there is strong two-dimensional electron gas localization below 100 K, while the thermally activated minority carriers with the activation energies of ϳ58 and ϳ218 meV contribute to the electron transport at high temperatures.

Scattering analysis of two-dimensional electrons in AlGaN/GaN with bulk related parameters extracted by simple parallel conduction extraction method

“…32 At room temperature and under 1.4 T magnetic field, Hall mobility and sheet carrier density of the investigated samples are 1724 cm 2 / V s and 7.95ϫ 10 12 cm −2 , respectively. At 22 K, electron mobility is calculated as high as 10766 cm 2 / V s. To calculate 2DEG and bulk contributions, SPCEM analysis is carried out with using the low magnetic field ͑0.05 T͒ and high magnetic field ͑1.4 T͒ Hall data as the input.…”

DX-center energy calculation with quantitative mobility spectrum analysis in n-AlGaAs/GaAs structures with low Al content

“…The dimensionless product of lowest mobility and the highest field must be greater than unity to clearly identify additional carriers (µ min B max 1). For the QMSA studies, µ min B max = 0.5 can be recommended as a limit [31]. In this study, this condition seems to be barely fulfilled for the mobilities of the latter carrier extracted by QMSA (µ min B max ∼ 0.3).…”

“…In many studies, including ours, 2DEG dominant Hall carrier densities are slightly increased with increasing temperature due to the thermal activation of bulk carriers at the barrier or other bulkrelated layer [31,33,34]. After implementing QMSA method, 2DEG densities mostly show temperature independent behavior [22,26,33,35,36].…”

“…This method is shown to be superior to other methods such as the two-carrier fit, multi carrier fit, and mobility spectrum analysis methods [27][28][29][30]. The analysis details are listed in our previous work for AlGaN/GaN based systems [31]. Fig.…”

Double subband occupation of the two-dimensional electron gas in InxAl1−xN/AlN/GaN/AlN heterostructures with a low indium content (0.064≤x≤0.140) barrier

“…The QMSA method is widely used in many studies to extract the mobilities and carrier densities of different carriers in semiconductor materials, including bulk samples, thin films, quantum wells, and multilayer device structures [14][15][16][17]. In addition, the mobilities and carrier densities of individual 2D and 3D electrons and holes in GaN-based heterostructures are reported with the implementation of the QMSA method [18,19]. Fig.…”