Toward h-BN/GaN Schottky Diodes: Spectroscopic Study on the Electronic Phenomena at the Interface

Abstract

Hexagonal boron nitride (h-BN), together with other members of the van der Waals crystal family, has been studied for over a decade, both in terms of fundamental and applied research. Up to now, the spectrum of h-BN-based devices has broadened significantly, and systems containing the h-BN/III-V junctions have gained substantial interest as building blocks in, inter alia, light emitters, photodetectors, or transistor structures. Therefore, the understanding of electronic phenomena at the h-BN/III-V interfaces becomes a question of high importance regarding device engineering. In this study, we present the investigation of electronic phenomena at the h-BN/GaN interface by means of contactless electroreflectance (CER) spectroscopy. This nondestructive method enables precise determination of the Fermi level position at the h-BN/GaN interface and the investigation of carrier transport across the interface. CER results showed that h-BN induces an enlargement of the surface barrier height at the GaN surface. Such an effect translates to Fermi level pinning deeper inside the GaN band gap. As an explanation, we propose a mechanism based on electron transfer from GaN surface states to the native acceptor states in h-BN. We reinforced our findings by thorough structural characterization and demonstration of the h-BN/GaN Schottky diode. The surface barriers obtained from CER (0.60 ± 0.09 eV for GaN and 0.91 ± 0.12 eV for h-BN/GaN) and electrical measurements are consistent within the experimental accuracy, proving that CER is an excellent tool for interfacial studies of 2D/III–V hybrids.

Towards n-type conductivity in hexagonal boron nitride

“…In previous work, the Schottky diodes based on undoped h-BN/GaN were reported 53 . The realization of n -type h-BN provides the possibility to fabricate advanced optoelectronic devices beyond the conventional group-III nitride material system.…”

Advances in Self-Powered Ultraviolet Photodetectors Based on P-N Heterojunction Low-Dimensional Nanostructures

“…So far, researchers have made a lot of efforts and many gratifying developments have been acquired, but self-powered UV photodetectors with higher performance are still highly desired. On the one hand, exploring novel nanostructures that can promote the separation of photogenerated e-h pairs and be prepared by simple and stable methods may still be an important direction in the future; on the other hand, with the emergence of new high-performance semiconductor materials (such as graphdiyne [ 104 , 105 , 106 , 107 , 108 , 109 , 110 , 111 ], h-BN [ 112 , 113 , 114 , 115 , 116 ], perovskites [ 117 , 118 , 119 , 120 , 121 , 122 , 123 , 124 , 125 , 126 , 127 ], black phosphorus [ 128 , 129 , 130 , 131 , 132 , 133 , 134 , 135 ], and MoS 2 [ 136 , 137 , 138 , 139 , 140 , 141 , 142 , 143 , 144 ]), the situation of inorganic semiconductors as leading materials in self-powered photodetectors may be changed. In addition, inspired by the rise of wearable photodetectors in recent years, the new generation of photodetectors needs to be designed to be more dexterous and intelligent, which obviously puts forward new requir...…”

Hexagonal Boron Nitride on III–V Compounds: A Review of the Synthesis and Applications

“…The position of the Fermi level on the surface is determined by the impurities and defects introduced during the growth process [31], thus affecting the performance of devices. Ewelina Zdanowicz et al [32] used the contactless electroreflectance (CER) method to study the electrical properties of the h-BN/GaN interface. They deposited a layer of h-BN thin film on GaN using the metal-organic chemical vapor deposition (MOCVD) technique (Figure 4a) and studied the properties of its interface effect.…”