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PdH is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Pd is bonded to four equivalent H atoms to form corner-sharing PdH4 tetrahedra. There is one shorter (1.82 Å) and three longer (1.85 Å) Pd–H bond length. H is bonded to four equivalent Pd atoms to form corner-sharing HPd4 tetrahedra.
VI is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. V is bonded to four equivalent I atoms to form distorted corner-sharing VI4 trigonal pyramids. There are one shorter (2.79 Å) and three longer (2.81 Å) V–I bond lengths. I is bonded to four equivalent V atoms to form distorted corner-sharing IV4 trigonal pyramids.
TlP is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Tl1+ is bonded to four equivalent P1- atoms to form corner-sharing TlP4 tetrahedra. There are three shorter (2.65 Å) and one longer (2.66 Å) Tl–P bond lengths. P1- is bonded to four equivalent Tl1+ atoms to form corner-sharing PTl4 tetrahedra.
MgH is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Mg is bonded to four equivalent H atoms to form corner-sharing MgH4 tetrahedra. There are three shorter (2.02 Å) and one longer (2.03 Å) Mg–H bond lengths. H is bonded to four equivalent Mg atoms to form corner-sharing HMg4 tetrahedra.
LiCl is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Li1+ is bonded to four equivalent Cl1- atoms to form corner-sharing LiCl4 tetrahedra. All Li–Cl bond lengths are 2.40 Å. Cl1- is bonded to four equivalent Li1+ atoms to form corner-sharing ClLi4 tetrahedra.
CIn is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. In3+ is bonded to four equivalent C3- atoms to form corner-sharing InC4 tetrahedra. There are one shorter (2.23 Å) and three longer (2.25 Å) In–C bond lengths. C3- is bonded to four equivalent In3+ atoms to form corner-sharing CIn4 tetrahedra.
AuCl is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Au1+ is bonded to four equivalent Cl1- atoms to form corner-sharing AuCl4 tetrahedra. All Au–Cl bond lengths are 2.61 Å. Cl1- is bonded to four equivalent Au1+ atoms to form corner-sharing ClAu4 tetrahedra.
GeC is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ge4+ is bonded to four equivalent C4- atoms to form corner-sharing GeC4 tetrahedra. There is three shorter (1.99 Å) and one longer (2.00 Å) Ge–C bond length. C4- is bonded to four equivalent Ge4+ atoms to form corner-sharing CGe4 tetrahedra.
BaO is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ba2+ is bonded to four equivalent O2- atoms to form corner-sharing BaO4 tetrahedra. All Ba–O bond lengths are 2.61 Å. O2- is bonded to four equivalent Ba2+ atoms to form corner-sharing OBa4 tetrahedra.
LaF is Wurtzite structured and crystallizes in the hexagonal P6_3/mmc space group. The structure is three-dimensional. La is bonded to five equivalent F atoms to form a mixture of edge and corner-sharing LaF5 trigonal bipyramids. There are three shorter (2.50 Å) and two longer (2.78 Å) La–F bond lengths. F is bonded to five equivalent La atoms to form a mixture of edge and corner-sharing FLa5 trigonal bipyramids.
IrH is Wurtzite structured and crystallizes in the hexagonal P6_3mc space group. The structure is three-dimensional. Ir is bonded to four equivalent H atoms to form distorted corner-sharing IrH4 trigonal pyramids. There is one shorter (1.77 Å) and three longer (1.90 Å) Ir–H bond length. H is bonded to four equivalent Ir atoms to form distorted corner-sharing HIr4 trigonal pyramids.
ZnGeN 2 is a wide bandgap material having less than 0.1% lattice mismatch with GaN and bandgap within few percent of that of GaN. Based on the first principle calculations, the valence band of ZnGeN 2 is situated ~1.4 eV above that of GaN at the heterointerface. Such a staggered band alignment between two closely lattice matched materials has already been demonstrated promising for novel optoelectronic device designs, for example, high efficiency blue and green light emitting diodes. However, the research on ZnGeN 2 is yet to pass the inceptive period. We report on the growth of single crystalline ZnGeN 2 films using metalorganic chemical vapor deposition and investigation on the crystalline, optical, electrical properties. Diethylzinc (DEZn), germane (GeH 4 ) and ammonia were used as the precursors for Zn, Ge and N, respectively. Films were grown on GaN and sapphire substrates. The Zn/Ge atomic ratio in the films determined from energy dispersive X-ray spectroscopy was found to decrease with increase in growth temperature but to increase with increase in pressure and DEZn/GeH 4 molar flow rate ratio. The X-ray diffraction (XRD) 2θ-ω spectra of the single crystalline ZnGeN 2 films resembled those of orthorhombic (perfectly ordered cations) or distorted wurtzite (disordered cations) polymorphs. High resolution scanning transmission electron microscopy imaging was used to further investigate the crystalline quality and crystalline structure of the films. The single crystalline films on c-sapphire or GaN substrates were found to have planar surface from scanning electron micrographs while those on r-sapphire substrate had stepped surface. No near band edge peak but a broad peak at ~2.05 eV was observed in the photoluminescence (PL) spectra, which was attributed to the transitions involving deep level defects. The PL excitation spectra peaked around 3.4 eV, which is due to the enhanced absorption of photons having energy close to the band gap. The as grown films were found to be n-type with 10 18 – 10 19 cm -3 carrier densities and mobility up to 17 cm 2 /V·s. In the end, the advancement made in this work regarding the growth of ZnGeN 2 thin films is a footstep towards the understanding of the material itself and in turn, towards the implementation of ZnGeN 2 based novel device designs.
Abstract Hexagonal boron nitride (h-BN) has attracted considerable interest as an ultrawide bandgap (UWBG) semiconductor. Experimental studies focused on the detailed near band-edge structure of h-BN at room temperature are still lacking. We report a direct experimental measurement of the near band-edge structure performed on h-BN quasi-bulk wafers via photocurrent excitation spectroscopy (PES). PES resolved the band-to-band transitions near M- and K-points in the Brillion zone (BZ), from which the room temperature indirect band gap of E g M K ∼6.02 eV, minimum direct bandgap at M-point of E g M = 6.36 eV and next lowest direct energy bandgap at K-point of E g K = 6.56 eV , have been simultaneously determined for the first time experimentally. The measured energy differences between K- and M-points in the conduction band minimum (CBM) and valence band maximum (VBM) are Δ E C M K = 0.54 eV and Δ E V M K = 0.34 eV, respectively, in good agreement with the calculation results. Significantly differing from its III-nitride wurtzite counterparts, in which only electrons and holes in the conduction and valence band extremes at the Γ-point are predominantly involved in the optical and transport processes, the results highlighted that charge carriers associated with both M- and K-valleys control to the optical excitation, recombination and charge transport processes in h-BN.
Single crystals of a new noncentrosymmetric polar oxysulfide SrZn2S2O (s.g. Pmn21) grown in a eutectic KF—KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS3O tetrahedra vertically separated from each other by Sr atoms and methods of making same.
Single crystals of a new noncentrosymmetric polar oxysulfide SrZn 2 S 2 O (s.g. Pmn2 1 ) grown in a eutectic KF-KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS3O tetrahedra vertically separated from each other by Sr atoms and methods of making same.
The effect of high-temperature annealing (HTA) treatments and Cd-excess during the in-situ doping of CdSeTe:Sb is investigated. Optimized treatments eliminate the wurtzite phase from the as-deposited CdSeTe layer, while facilitating Se intermixing and grain size enhancement before CdCl2 treatment. The improved device stack quality results in a VOC improvement of 250 mV. VOC is further improved by tuning the Cd/Sb flux ratio during CdSeTe:Sb deposition. The lowest defect concentration is achieved at Cd/Sb of 1.4:1, which produced the best VOC CdSeTe:Sb cell with VOC = 849mV, despite a decreased carrier concentration due to the harsh CdCl2 treatment.
Single crystals of a new noncentrosymmetric polar oxysulfide SrZn 2 S 2 O (s.g. Pmn2 1 ) grown in a eutectic KF-KCl flux with unusual wurtzite-like slabs consisting of close-packed corrugated double layers of ZnS 3 O tetrahedra vertically separated from each other by Sr atoms and methods of making same.
Ferroelectric materials promise exceptional attributes including low power dissipation, fast operational speeds, enhanced endurance, and superior retention to revolutionize information technology. However, the practical application of ferroelectric-semiconductor memory devices has been significantly challenged by the incompatibility of traditional perovskite oxide ferroelectrics with metal-oxide-semiconductor technology. Recent discoveries of ferroelectricity in binary oxides such as Zn 1-x Mg x O and Hf 1-x Zr x O have been a focal point of research in ferroelectric information technology. Here, this work investigates the ferroelectric properties of Zn 1-x Mg x O utilizing automated band excitation piezoresponse force microscopy. This findings reveal the coexistence of two ferroelectric subsystems within Zn 1-x Mg x O. A “fringing-ridge mechanism” of polarization switching is proposed that is characterized by initial lateral expansion of nucleation without significant propagation in depth, contradicting the conventional domain growth process observed in ferroelectrics. This unique polarization dynamics in Zn 1-x Mg x O suggests a new understanding of ferroelectric behavior, contributing to both the fundamental science of ferroelectrics and their application in information technology.