Wide-bandgap semiconductor materials: For their full bloom

Abstract

Wide-bandgap semiconductors are expected to be applied to solid-state lighting and power devices, supporting a future energy-saving society. While GaN-based white LEDs have rapidly become widespread in the lighting industry, SiC-and GaN-based power devices have not yet achieved their popular use, like GaN-based white LEDs for lighting, despite having reached the practical phase.What are the issues to be addressed for such power devices? In addition, other wide-bandgap semiconductors such as diamond and oxides are attracting focusing interest due to their promising functions especially for power-device applications. There, however, should be many unknown phenomena and problems in their defect, surface, and interface properties, which must be addressed to fully exploit their functions. In this review, issues of wide-bandgap semiconductors to be addressed in their basic properties are examined toward their "full bloom".

Analysis of reaction between c+a and -c+a dislocations in GaN layer grown on 4-inch Si(111) substrate with AlGaN/AlN strained layer superlattice by transmission electron microscopy

“…[1][2][3] GaN growth on a Si substrate is one of the most useful methods for providing large-area GaN wafers at a low cost. [4][5][6][7][8] As aresult of several breakthroughs, 9,10 an AlGaN/GaN HEMT on Si demonstrated a breakdown voltage of over 1400 V. 10 Unfortunately, the large lattice and thermal expansion mismatches between Si and GaN produce high-density dislocations in a GaN layer. [11][12][13] Decreasing the dislocation density in a GaN layer has been a major issue because the dislocations are considered to deteriorate the reliability and life of devices.…”

Magnetron Sputter Epitaxy of High-Quality GaN Nanorods on Functional and Cost-Effective Templates/Substrates

“…Gallium nitride (GaN) and related III-nitride semiconductor alloys represent the dominating technology in solid-state lighting (SSL) for fabrication of light-emitting diodes (LED), laser diodes (LD), and power devices [1][2][3][4]. These devices are usually fabricated on sapphire or silicon carbide (SiC) substrates.…”

“…Another ceramic material with a similar property envelope as ZrB 2 is the NaCl structured (B1) TiN, with a moderate lattice mismatch of 6% to GaN and with a work function matched to the Fermi level of n-GaN for forming a low-resistant ohmic contact [10]. An additional advantage for ZrB 2 and TiN as electrodes in optoelectronic devices is that…”

Electronic and optical properties of ternary alloys ZnxCd1−xS, ZnxCd1−xSe, ZnSxSe1−x, MgxZn1−xSe

“…A particular attention has been devoted in the literature to the wide-gap semiconductor alloys for applications in the fields of optical devices technology [1,2]. Several authors have investigated different kinds of materials in order to search for the desired parameters, such as band-gap, lattice constant, dielectric constant and carrier mobility [3][4][5][6].…”