CHAPTER 8. The Group III-Nitride Material Class: from Preparation to Perspectives in Photoelectrocatalysis

Abstract

In this chapter, the physical properties of group III-nitride compound semiconductors are reviewed in the context to act as semiconducting material in photoelectrocatalytic solar fuel structures. The band alignments in the InN-GaN-AlN-InN alloy system are summarized and discuss with respect to potential catalysts HOMO and LUMO states, providing efficient charge transfer in photoelectrochemical cell structures. The present status in group III-nitride materials fabrication and ternary alloy formation, stabilization and integration into envisioned materials structures is presented, together with challenges that have to be addressed to enable the full potential of group III-nitrides to contribute to high-efficient energy generation and utilization.

Development of 2-D Boron Nitride Nanosheets UV Photoconductive Detectors

“…This means that the average of the lattice constant of the crystalline structure increases up to 5% according to Bragg formulation of XRD. Since the bandgap width or energy is normally inversely proportional to the lattice constant for III-V nitride materials [17], we conclude that the bandgap width of 2-D sheet decreases at least down to 5%. Because of the variation of the bandgap width due to the decrease in thickness, we expect that there would be a shift of cutoff wavelength for the superthin BNNSs-based UV photodetector.…”

High Operating Temperature and Low Power Consumption Boron Nitride Nanosheets Based Broadband UV Photodetector

“…The phenomenon of increased interspacing or lattice constant in the BNNSs was also confirmed by the observed peak shift in the XRD spectrum. Because the bandgap width of III-V nitride materials is generally inversely proportional to the lattice constant54, it is expected the decrease of the bandgap width of 2D BNNSs would unavoidably result in a red shift in cutoff wavelength. In fact, the red shift was already observed in our recent experiments with super thin BNNS based photodetectors that exhibited a sharp cut-off wavelength down to 250 nm41, an almost 8% shift from the cut-off wavelength of 230 nm for the bulk BN based photodetectors47.…”

High mobility and high concentration Type-III heterojunction FET

“…However, it was a surprise to discover that new energy bands resulted [2,3]. It was interesting that the following important feature appeared, namely that carrier transfer occurred without even having the need to apply a voltage [4,5]. The valence band maximum of GaSb lies slightly above the conduction band minimum of the InAs, creating electron transfer from the valence band of GaSb into the empty conduction band of InAs, in other words resulting carrier transfer without the need to apply a voltage!…”

“…Note that the valence band maximum of GaSb is above the conduction band minimum of InAs, allowing carrier transfer from the full valence band into the empty conduction band [4,5].…”