Investigaton of morphologic and electrical properties of nitride-based (III-V) semiconductor?s heterostructure

Morphologic, structural and electrical properties of GaN(cap)/Al0.3Ga0.7N/AIN heterostructure were investigated. The screw type dislocation density on the GaN surface of the heterostructure was measured as ~108 cm-2. Its growth has been shown as step-flow mode with the surface analysis. The crystal quality and epitaxial layers of the heterostructure were verified with the structural analysis. Carrier density (nH) and mobility (µ) values were measured in the temperature range of 20-350 K by Hall effect analysis. As a result the heterostructure exhibited 2DEG type structure. Current-voltage (I-V), capacitance-voltage (C-V) and conductance-voltage (G/w-V) measurements were carried out in the temperature range of 295-415 K by creating ohmic and Schottky contacts on the surface. Parameters like the ideality factor (n), series resistance (Rs), barrier height (?B), interface state density (Nss), carrier density (ND) were calculated of which were determined from I-V, C-V and G/w-V measurements. Mean barrier height ( ) and Richardson constant (A*) were also calculated using Gaussian distribution function and were compared with theoretical results.