Interface state density of free-standing GaN Schottky diodes

Abstract

Schottky diodes were fabricated on the HVPE-grown, free-standing gallium nitride (GaN) layers of n-and p-types. Both contacts (ohmic and Schottky) were deposited on the top surface using Al/Ti and Pd/Ti/Au, respectively. The Schottky diode fabricated on n-GaN exhibited double barriers with values of 0.9 and 0.6 eV and better performance in the rectification factor together with reverse and forward currents with an ideality factor of 1.8. The barrier height for the p-GaN Schottky diode is 0.6 eV with an ideality factor of 4.16. From the capacitance-voltage (C-V) measurement, the net doping concentration of n-GaN is 4 × 10 17 cm −3 , resulting in a lower reverse breakdown of around −12 V. The interface state density (N SS ) as a function of E C −E SS is found to be in the range 4.23 × 10 12 -3.87 × 10 11 eV −1 cm −2 (below the conduction band) from Ec-0.90 to E C -0.99. Possible reasons responsible for the low barrier height and high ideality factor have been addressed.

Wet Chemical Functionalization of III–V Semiconductor Surfaces: Alkylation of Gallium Arsenide and Gallium Nitride by a Grignard Reaction Sequence

“…Surface modification strategies utilizing oxidized surfaces (e.g., silanization, phosphonate chemisorption) − are problematic for GaAs, GaP, and GaN surfaces in many optoelectronic applications. Oxidized Ga-based III–V semiconductor interfaces unavoidably contain large quantities of electronic surface traps (i.e., ≥ 10 13 defects·cm –2 ). , For example, in the context of solar energy conversion applications, surface-mediated charge recombination at interfacial defects is a deleterious, parasitic pathway . Modification schemes based on oxidized surfaces are wholly inappropriate and incompatible.…”

“…Oxidized Ga-based III−V semiconductor interfaces unavoidably contain large quantities of electronic surface traps (i.e., ≥ 10 13 defects•cm −2 ). 77,78 For example, in the context of solar energy conversion applications, surface-mediated charge recombination at interfacial defects is a deleterious, parasitic pathway. 79 Modification schemes based on oxidized surfaces are wholly inappropriate and incompatible.…”

Modification of contact properties in Pt/n-GaN Schottky junctions with ZnO and TiO2/ZnO interlayers

“…F The barrier heights were calculated to be 1.54, 1.63, and 1.78 eV for the Pt/GaN, Pt/ZnO, and Pt/ZnO/TiO 2 /GaN junctions, respectively. A higher barrier height from C-V compared with that from J-V methods is associated with contamination at the interfaces, interface states, fixed surface polarization charges, and deep impurity levels [43].…”

ZnO Nanowire Based Photoelectrical Resistive Switches for Flexible Memory

“…Other mechanisms such as tunneling, recombination, interfacestate-assisted transport or a rough semiconductor surface are likely present. [16][17][18] The resistive switching behavior of a single or multiple ZnO nanowire device under dark conditions is shown in Figure 1h. In this paper, the main criteria for bias sweeping direction are originated from the effective diode under dark condition.…”