Electrical characteristics of vertical-geometry Schottky junction to magnetic insulator (Ga,Mn)N heteroepitaxially grown on sapphire

TL;DR

This study measures the electrical properties of a vertical Schottky junction with (Ga,Mn)N on sapphire, revealing high resistance and barrier characteristics similar to other GaN-based devices, with implications for device performance.

Contribution

First-time establishment of Schottky barrier height and ideality factor for (Ga,Mn)N using a vertical device on sapphire, highlighting electrical properties and potential current blocking mechanisms.

Findings

High resistance (>10 MΩ) at room temperature indicates low dislocation density.

Schottky barrier height close to other metal/GaN junctions.

Large ideality factor suggests significant current blocking or serial resistance.

Abstract

Schottky barrier height and the ideality factor $\eta$ are established for the first time in the single phase (Ga,Mn)N using a vertical geometry device. The material has been heteroepitaxially grown on commercially available low threading dislocation density GaN:Si template. The observed above 10M$\Omega$ resistances already at room temperature are indicative that a nearly conductive-dislocation-free electrical properties are achieved. The analysis of temperature dependence of the forward bias I-V characteristics in the frame of the thermionic emission model yields Ti-(Ga,Mn)N Schottky barrier height to be slightly lower but close in character to other metal/GaN junctions. However, the large magnitudes of the ideality factor $\eta$>1.5 for T$\leqslant$300K, point to a sizable current blocking in the structure. While it remains to be seen whether it is due to the presence of (Ga,Mn)N barrier or due to other factors which reduce the effective area of the junction, an existence of a substantial serial resistance may hold the key to explain similar observations in other devices of a corresponding structure and technological relevance.