研究目的
To accurately determine the bulk carrier concentration in narrow bandgap p-type InAsSb using magnetic-field-dependent electrical transport measurements in conjunction with Multi-Carrier Fit (MCF) analysis to extract the properties of the different carrier species present.
研究成果
The study successfully characterized the transport properties of Be-doped, lattice-matched, InAs0.91Sb0.09 on GaSb using temperature and magnetic-field-dependent measurements in conjunction with Multi-Carrier Fit analysis. The bulk hole concentrations and mobilities at 77 K (300 K) were determined to be 1.6×1018 cm-3 (2.3×1018 cm-3) and 125 cm2 V-1 s-1 (60 cm2 V-1 s-1), respectively. A surface treatment experiment correlated one of the electron conducting populations to the surface, and variable temperature measurements enabled the extraction of the bulk hole, interface carriers, and surface electron transport properties.
研究不足
The study acknowledges the challenge of accurately determining the hole carrier concentration in narrow bandgap InAsSb due to the potential for electron accumulation at the surface of the material and at its interface with the layer grown directly below it. The maximum magnetic-field strength of the Hall-effect measurement system dictates the lowest possible measurable mobility.
1:Experimental Design and Method Selection:
The study utilized temperature- and magnetic-field-dependent transport measurements in conjunction with Multi-Carrier Fit analysis on a series of p-doped InAs
2:91Sb09 samples on GaSb substrates. Sample Selection and Data Sources:
The sample was grown on an n-type (Te-doped) GaSb substrate using Molecular Beam Epitaxy (MBE). The structure consisted of a 2 μm thick lattice-matched InAs
3:91Sb09 bulk layer with a target p-type Be-doping concentration of 2×1018 cm-3 grown on top of a 01 μm thick undoped GaSb buffer layer on a 5 μm thick lattice-matched and undoped AlAs08Sb92 insulating layer. List of Experimental Equipment and Materials:
Dark variable-field Hall measurements were performed on a Lakeshore 9509 Hall Measurement System (HMS) with a 9-Tesla maximum magnetic field intensity at a current of 100 μA.
4:Experimental Procedures and Operational Workflow:
The wafer was cleaved, and pieces from the wafer were wet-etched using a citric acid solution to different thicknesses. Standard optical photolithography was used to define 5 mm × 5 mm square mesas in van der Pauw (VDP) configuration.
5:Data Analysis Methods:
The data was analyzed by the Mobility Spectrum Analysis (MSA) and Multi-Carrier Fit (MCF) to identify the different conducting carrier populations and their respective mobilities in the structure.
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