Bulk Crystal Growth Research Articles

Reporting a novel visible near-infrared {Tb3}[Ga0.1Sc1.9](Al3)O12 single crystal for Faraday isolators

A {Tb3}[Ga0.1Sc1.9](Al3)O12 crystal is designed and investigated for the first time. This novel single crystal exhibits excellent magneto-optical properties and is very promising for visible near-infrared Faraday applications.

The first polyanion-substitution-driven centrosymmetric-to-noncentrosymmetric structural transformation realizing an excellent nonlinear optical supramolecule [Cd4P2][CdBr4

Crystallographically, noncentrosymmetricity (NCS) is an essential precondition and foundation of achieving nonlinear optical (NLO), pyroelectric, ferroelectric, and piezoelectric materials. Herein, structurally, octahedral [SmCl6]3- is substituted by the acentric tetrahedral polyanion [CdBr4]2-, which is employed as a templating agent to induce centrosymmetric (CS)-to-NCS transformation based on the new CS supramolecule [Cd5P2][SmCl6]Cl (1), thereby providing the NCS supramolecule [Cd4P2][CdBr4] (2). Meanwhile, this replacement further results in the host 2D ∞2[Cd5P2]4+ layers converting to yield the twisted 3D ∞3[Cd4P2]2+ framework, which promotes the growth of bulk crystals. Additionally, phase 2 possesses well-balanced NLO properties, enabling considerable second-harmonic generation (SHG) responses (0.8-2.7 × AgGaS2) in broadband spectra, the thermal expansion anisotropy (2.30) together with suitable band gap (2.37 eV) primarily leading to the favorable laser-induced damage threshold (3.33 × AgGaS2), broad transparent window, and sufficient calculated birefringence (0.0433) for phase-matching ability. Furthermore, the first polyanion substitution of the supramolecule plays the role of templating agent to realize the CS-to-NCS transformation, which offers an effective method to rationally design promising NCS-based functional materials.

Photoluminescence microscopy as a noninvasive characterization method for defects in gallium oxide and aluminum gallium oxide epitaxial films

Herein we utilize polarized photoluminescence (PL) microscopy and spectral analysis to locate and characterize many different types of µm-scale extended defects present in melt-grown bulk crystals and metal-organic vapor-phase epitaxy (MOVPE)-grown epitaxial thin films of β-Ga2O3 and β-(Al,Ga)2O3. These include pits, divots, mounds, scratches, rotation domain boundaries, stacking faults, cracks, and other defect categories. Some types of µm-scale defects simply decrease overall PL yield, while others emit different spectra than single crystal regions. We combine PL microscopy with atomic force microscopy (AFM) and scanning electron microscopy (SEM) to provide detailed characteristics of these different types of features which can arise from both bulk crystal growth, surface preparation, and epitaxial growth processes. We show that sample quality (in terms of extended defects) can be determined by using PL and that attributing spectral features to isolated point defects is invalid unless the sample is proven to not contain extended defects.

Viewing SiGe Heterostructure for Qubits with Dislocation Theory

SiGe/Si/SiGe heterostructure serves as one of the ideal semiconductor material system to build large scale electron spin qubits[1]. To further push the scalability and extend the coherence times of qubits built on SiGe/Si/SiGe heterostructures, there are several factors to improve, one of that is the lattice homogeneity of strained Si. One source of lattice homogeneity break down are dislocations. Due to the difficulties of high quality SiGe bulk crystal growth [2-3], relaxed SiGe is commonly grown on Si substrates by epitaxy. Viewing the SiGe/Si/SiGe heterostructure on native Si substrate, dislocations half loops form unavoidably because of the misfit between SiGe and the Si substrate. These dislocation half loops consist of threading segments extending through the whole heterostructure (figure 1 (a) and (c)) [4]. Due to the stress caused by the strained Si quantum well layer, the threading dislocations can be driven to glide, resulting in additional misfit segments in the lower interface of strained Si layer when the critical thickness is exceeded (figure 1 (b)) [5]. The extension of these misfit segments is blocked when they meet other perpendicular dislocations (figure 1 (d)) [6]. These misfit dislocations destroy strain uniformity and cause tilt inside the Si layer, resulting in a distortion of the valley splitting and ultimately, reducing the coherence time of qubits [7-8].In this work, we present the observation of dislocations in SiGe/Si/SiGe heterostructures for qubit application by plan-view TEM (Figure 1 (right)). Here, the experimental observations agree with dislocation theory that threading dislocations (some are marked by (b)) will glide and elongate to have misfit segments (some are marked by (c)) in the interface when two requirements are fulfilled: misfit exists between epitaxial layer and substrate; critical thickness is exceeded. When the misfit dislocations meet perpendicular misfit dislocation line, they are blocked since the thickness is not enough to glide over it [6]. This is the case in figure 1 right marked by (d). Due to the misfit segment generation and blocking effects, the misfit dislocation spacing is proportional to the threading dislocation density both theoretically and experimentally. These misfit dislocations bring local strain field around them [9], which disturb the desired homogeneous strain field by misfit. Therefore, misfit dislocation generation needs to be suppressed if one wants to achieve homogeneous strain in Si thin layer in large scale.According to Matthews-Blakeslee theory, one can avoid the formation of misfit dislocations in the Si interface by controlling the strained layer within the critical thickness. The critical thickness of Si on Si0.7Ge0.3 is calculated as 8.5 nm. The Electron channeling contrast images of Si with difference thickness 10 nm and 5 nm grown on high threading dislocation relaxed Si0.7Ge0.3 buffer at 700°C by reduced pressure chemical vapor deposition in Figure 2 are collaborating with theory: obviously misfit dislocation appear in 10 nm Si on relaxed Si0.7Ge0.3 (Figure 2 (left)) and no misfit dislocation are presented in 5 nm Si on Si0.7Ge0.3 (Figure 2 (right)).Our results show that dislocation generation and movement needs to be taken into consideration to further develop SiGe heterostructure based qubits.

(Invited) Progress in Elucidating the Growth Process for Basic Ammonothermal GaN

Gallium nitride (GaN) is an attractive materials platform for the pursuit of high-power, high-efficiency (opto-)electronic devices. Key to allowing this wide band gap material system to achieve its full potential is the availability of low-cost, large-area, high-crystal-quality native substrates. While important advances have been made to this effect, continued progress and breakthroughs are required to truly meet this objective.The ammonothermal method, which utilizes supercritical ammonia to preferentially dissolve and crystalize GaN on a native seed, offers a true bulk crystal growth process to yield large, inexpensive GaN substrates. To further enhance the growth rate and quality of GaN, much still needs to be learned and gained from an improved understanding of the chemical processes and growth mechanisms occurring in the ammonothermal environment. A key challenge to achieving this, is the difficulty in obtaining in-situ information during growth of GaN due to the use of thick-walled autoclaves containing the corrosive environment at temperatures up to ~ 650 °C and pressures up to ~ 2500 atm.This talk will present the progress made in our understanding of the underpinnings of the basic ammonothermal growth of GaN. Specifically, it will discuss advances made to allow us to understand the thermodynamic foundation of the solvent, for the first time. This is achieved by the creation and application of a new, simple equation of state for supercritical ammonia under ammonothermal conditions. Additionally, by combining this solvent knowledge with in-situ temperature, total system measurements, and GaN single crystal growth, various aspects of the crystal growth process and solute behaviors are elucidated and will be presented. Consequences towards our ability to enhance the growth rate of basic ammonothermal GaN will then be discussed.

High-Energy Computed Tomography as a Prospective Tool for In Situ Monitoring of Mass Transfer Processes inside High-Pressure Reactors-A Case Study on Ammonothermal Bulk Crystal Growth of Nitrides including GaN.

For the fundamental understanding and the technological development of the ammonothermal method for the synthesis and crystal growth of nitrides, an in situ monitoring technique for tracking mass transport of the nitride throughout the entire autoclave volume is desirable. The feasibility of using high-energy computed tomography for this purpose was therefore evaluated using ex situ measurements. Acceleration voltages of 600 kV were estimated to yield suitable transparency in a lab-scale ammonothermal setup for GaN crystal growth designed for up to 300 MPa operating pressure. The total scan duration was estimated to be in the order of 20 to 40 min, which was sufficient given the comparatively slow crystal growth speed in ammonothermal growth. Even shorter scan durations or, alternatively, lower acceleration voltages for improved contrast or reduced X-ray shielding requirements, were estimated to be feasible in the case of ammonoacidic growth, as the lower pressure requirements for this process variant allow for thinned autoclave walls in an adapted setup designed for improved X-ray transparency. Promising nickel-base and cobalt-base alloys for applications in ammonothermal reactors with reduced X-ray absorption in relation to the maximum operating pressure were identified. The applicability for the validation of numerical simulations of the growth process of GaN, in addition to the applicability of the technique to further nitride materials, as well as larger reactors and bulk crystals, were evaluated.

Numerical Analysis of Gas Flow Instabilities in Simplified Vertical HVPE GaN Reactors

This paper investigates the gas flow and the mass transport in simplified axial-symmetric vertical HVPE reactors for the growth of GaN bulk crystals through numerical simulations. We evaluate the relative significance of different flow and transport phenomena in dependence on the direction of gravity. The performed simulations show that buoyancy effects due to density differences between neighboring gas lines are the main factor causing the deformation of laminar flow patterns and the formation of recirculation cells within the growth zone. Baroclinic instabilities have been identified as the source for these phenomena. In contrast, typical vertical temperature gradients show only a minor impact on the stability of the gas flow within the growth zone in the vicinity of the growing crystal. Based on these results, major differences of the species transport in vertical HVPE reactors, where the flow is parallel or anti-parallel to the direction of gravity, referred to as down-flow and up-flow, respectively, are summarized. The performed analysis of the interplay and relative significance of different flow effects in the HVPE environment allows a general recommendation for reactor design and scaling with respect to stable gas flow conditions within the growth zone.

Synthesis of Graphene and Related Materials by Microwave-Excited Surface Wave Plasma CVD Methods

Several kinds of chemical vapor deposition (CVD) methods have been extensively used in the semiconductor industries for bulk crystal growth, thin film deposition, and nanomaterials synthesis. In this article, we focus on the microwave-excited surface wave plasma CVD (MW-SWP CVD) method for growth of graphene and related materials. The MW-SWP CVD system consisting of waveguide, slot antenna, and dielectric windows is significant for generating high density plasma with low electron temperature, enabling low temperature growth of materials without damaging the surface of base substrates. The synthesis of graphene and hexagonal boron nitride (hBN) films has been achieved on metals, semiconductors, insulators, and dielectric substrates for application in photovoltaics, sensors, batteries, supercapacitors, fuel cells, and various other electronic devices. The details of the synthesis process for graphene films, vertically-oriented graphene, doped-graphene, and hBN films by the MW-SWP CVD method are summarized to understand the growth mechanism, which will enable further development of the plasma CVD process for material synthesis at a low temperature for industrial applications.

The impact of feedstock size and composition on the hydrothermal growth of (U,Th)O2

Bulk crystal growth of refractory oxides requires unique approaches, and the UxTh1-xO2 solid solution is no exception. Hydrothermal transport reactions of U0.1Th0.9O2 onto ThO2 seeds with feedstocks comprised of U0.1Th0.9O2 or mixtures of UO2 and ThO2 with a nominal composition of U0.1Th0.9O2 are investigated with µ-Raman spectroscopy and X-ray fluorescence. In each case, the trends in stoichiometry as a function of distance from the seed are analyzed and the deviations from the nominal stoichiometry discussed. When the feedstock is composed of mixed oxides, the particle surface area’s influence on the feedstock dissolution rate is the dominant factor and can produce U-rich stoichiometries as high as U0.75Th0.25O2. When composed solely of U0.1Th0.9O2, the total growth amount depends on the particle size, but the obtained stoichiometry is the product of differing solubilities. Although the U0.1Th0.9O2 feedstock produces the most homogeneous growth, the ending growth of the smallest particle UO2/ThO2 mixture yields the stoichiometry closest to U0.1Th0.9O2. How to obtain desired stoichiometries from mixtures by matching the particle size and solubilities is briefly discussed.

Electrical, Optical, and Structural Stability Over Ten Years for Sb Based III-V Semiconducting Bulk Grown by VDS

III-V semiconductors have an advantage of not being degraded with time at room temperature, among non-silica semiconductors. This stability property is useful at the places where frequent device replacement is not possible. Determination of stability parameters are needed to be studied prior to their application as a junction substrate. The Vertical Directional Solidification (VDS) technique is employed for the growth of bulk crystals, without the seed, without contact to the ampoule wall, without coating, and without external pressure. The antimony based III-V substrates have been studied before and after an interval of ten years for any possible degradation in quality that may affect their applicability. XRF, EDAX, FTIR, XRD, Raman, and resistivity measurements methods were used to measure compositional optical, structural, and electrical consistency over the time. These bulk crystals revealed a high degree of stability within experimental limits for more than ten years, including intact crystalline structure, no formation of oxides, compositional stability, and no significant variation in band gap and resistivity, and hence still appropriate to be applied in semiconductor junction fabrications.

TinyLev acoustically levitated water: Direct observation of collective, inter-droplet effects through morphological and thermal analysis of multiple droplets

HypothesisUnderstanding the crystallization of atmospheric water can require levitation techniques to avoid the influence of container walls. Recently, an acoustic levitation device called the TinyLev was designed, which can levitate multiple droplets at room temperature. Proximal crystallization may affect droplet phase change and morphological characteristics. MethodologyIn this study, acoustically levitated pure water droplets were frozen individually and in pairs or triplets using a TinyLev device. Nucleation, bulk crystal growth, and melting were observed using digital and infrared cameras concurrently. FindingsInitially, the acoustic field forced the droplets into an oblate spheroid shape, though the counteracting force of the cooling stream caused them to circularize. Droplet geometry was thus the net result of streaming forces and surface tension at the acoustic boundary layer/air–liquid interface. Nucleation was determined to be neither homogeneous nor heterogeneous but secondary, and thus dependent on the cooling rate and not on the degree of supercooling. It was likely initiated by aerosolized ice particles from the air or from droplets that had already nucleated and broken up. The latter secondary ice production process resulted in multi-drop systems with statistically identical nucleation times. Notably, this meant that the presence of interfacial rupture at an adjacent droplet could influence the crystallization behaviour of another. After the formation of an initial ice shell around the individual droplets, dendritic protrusions grew from the droplet surface, likely seeded by the same ice particles that caused nucleation, but at a quasi-liquid layer. When freezing was complete, it was determined that the frozen core had undergone a volumetric expansion of 30.75%, compared to 9% for pure, sessile water expansion. This significantly greater expansion may have resulted from entrained air bubbles at the inner solid–liquid interface and oscillations at the moving phase boundary caused by changes in local acoustic forces. Soon after melting began, acoustic streaming, the buoyancy of the remaining ice, and convective currents caused by both an inner thermal gradient and thermocapillary effects along the air–liquid interface, all contributed to the droplet spinning about the horizontal axis.

The bulk crystal growth in binary supercooled melts with allowance for heat removal

The bulk crystal growth in binary supercooled melts with allowance for heat removal

Disrupting Crystal Growth through Molecular Recognition: Designer Therapies for Kidney Stone Prevention.

Aberrant crystallization within the human body can lead to several disease states or adverse outcomes, yet much remains to be understood about the critical stages leading to these events, which can include crystal nucleation and growth, crystal aggregation, and the adhesion of crystals to cells. Kidney stones, which are aggregates of single crystals with physiological origins, are particularly illustrative of pathological crystallization, with 10% of the U.S. population experiencing at least one stone occurrence in their lifetimes. The human record of kidney stones is more than 2000 years old, as noted by Hippocrates in his renowned oath and much later by Robert Hooke in his treatise Micrographia. William Hyde Wollaston, who was a physician, chemist, physicist, and crystallographer, was fascinated with stones, leading him to discover an unusual stone that he described in 1810 as cystic oxide, later corrected to cystine. Despite this long history, however, a fundamental understanding of the stages of stone formation and the rational design of therapies for stone prevention have remained elusive.This Account reviews discoveries and advances from our laboratories that have unraveled the complex crystal growth mechanisms of l-cystine, which forms l-cystine kidney stones in at least 20 000 individuals in the U.S. alone. Although l-cystine stones affect fewer individuals than common calcium oxalate stones, they are usually larger, recur more frequently, and are more likely to cause chronic kidney disease. Real-time in situ atomic force microscopy (AFM) reveals that the crystal growth of hexagonal l-cystine is characterized by a complex mechanism in which six interlaced anisotropic spirals grow synchronously, emanating from a single screw dislocation to generate a micromorphology with the appearance of stacked hexagonal islands. In contrast, proximal heterochiral dislocations produce features that appear to be spirals but actually are closed loops, akin to a Frank-Read source. These unusual and aesthetic growth patterns can be explained by the coincidence of the dislocation Burgers vector and the crystallographic 61 screw axis. Inhibiting l-cystine crystal growth is key to preventing stone formation. Decades of studies of "tailor-made additives", which are imposter molecules that closely resemble the solute and bind to crystal faces through molecular recognition, have demonstrated their effects on crystal properties such as morphology and polymorphism. The ability to visualize crystal growth in real time by AFM enables quantitative measurements of step velocities and, by extension, the effect of prospective inhibitors on growth rates, which can then be used to deduce inhibition mechanisms. Investigations with a wide range of prospective inhibitors revealed the importance of precise molecular recognition for binding l-cystine imposters to crystal sites, which results in step pinning and the inhibition of step advancement as well as the growth of bulk crystals. Moreover, select inhibitors of crystal growth, measured in vitro, reduce or eliminate stone formation in knockout mouse models of cystinuria, promising a new pathway to l-cystine stone prevention. These observations have wide-ranging implications for the design of therapies based on tailor-made additives for diseases associated with aberrant crystallization, from disease-related stones to "xenostones" that form in vivo because of the crystallization of low-solubility therapeutic agents such as antiretroviral agents.

Fast crystal growth of amorphous nimesulide: implication of surface effects.

Understanding crystallization behaviors is of utmost importance for developing robust amorphous pharmaceutical solids. Herein, the crystal growth behaviors of amorphous anti-inflammatory drug nimesulide (NIME) are systemically investigated in the glassy and supercooled liquid state as a function of temperature. A sudden over-tenfold increase is observed in the bulk crystal growth of NIME on cooling below its glass transition temperature (Tg). This fast growth behavior is known as a glass-to-crystal (GC) mode and has been reported in some molecular glasses. Fast surface crystal growth of NIME can persist up to Tg + 57°C with a weak jump in its growth rates at 30-40°C. In addition, surface crystal growth and GC growth of NIME exhibit an almost identical temperature dependence, supporting the view that GC growth is indeed a surface-facilitated process. Moreover, the bubble-induced fast crystal growth of NIME is observed in the interior of its supercooled liquid with approximately the same growth kinetics as surface crystal growth. These findings are relevant for a full understanding of the surface-related crystallization behaviors and physical stability of amorphous pharmaceutical formulations.

Study of the effect of Mn:Bi ratio in the growth of MnBi2Te4 bulk crystals

The antiferromagnetic topological insulator MnBi2Te4 has drawn great interest in recent years. However, techniques for the growth of sizeable single crystals still need to be improved. Mn:Bi ratio or MnTe:Bi2Te3 ratio in the starting material is an important factor that affects the outcome of synthesis. We employed a relatively simple self-flux method that uses the three elements directly and involves only one sintering procedure. We systematically studied the crystals obtained with different Mn:Bi ratio, from 1:2 (the stoichiometric ratio) to 1:20. Structural characterization shows the shift in the chemical compositions, from entirely MnBi2Te4 septuple-atomic layers, to the MnBi4Te7 structure and finally to Mn-doped Bi2Te3. Hybrid crystals with multiple types of structures are found among them. The relation between the results and the starting material ratios is summarized, and can provide useful reference for the crystal growth and future researches in this area.

Formation of a single quasicrystal upon collision of multiple grains

Quasicrystals exhibit long-range order but lack translational symmetry. When grown as single crystals, they possess distinctive and unusual properties owing to the absence of grain boundaries. Unfortunately, conventional methods such as bulk crystal growth or thin film deposition only allow us to synthesize either polycrystalline quasicrystals or quasicrystals that are at most a few centimeters in size. Here, we reveal through real-time and 3D imaging the formation of a single decagonal quasicrystal arising from a hard collision between multiple growing quasicrystals in an Al-Co-Ni liquid. Through corresponding molecular dynamics simulations, we examine the underlying kinetics of quasicrystal coalescence and investigate the effects of initial misorientation between the growing quasicrystalline grains on the formation of grain boundaries. At small misorientation, coalescence occurs following rigid rotation that is facilitated by phasons. Our joint experimental-computational discovery paves the way toward fabrication of single, large-scale quasicrystals for novel applications.

Bulk crystal growth and mechanical and spectroscopic features comparison of Dy3+-doped (LuxY1-x)3Al5O12（x = 0, 1/3, 1/2, 2/3）single crystals for yellow lasers

A series of high-quality Dy3+-doped (LuxY1-x)3Al5O12 (x = 0, 1/3, 1/2, 2/3, abbr. as Dy3+: LuYAG) crystals have been grown by the Czochralski method, namely Dy3+: Y3Al5O12, Dy3+: LuY2Al5O12, Dy3+: Lu1.5Y1.5Al5O12, and Dy3+: Lu2YAl5O12 crystals with similar Dy3+ concentration of 4 at%. Such crystals were investigated and compared through the measurements of their mechanical and spectral characteristics like absorption, emission spectra, and fluorescence decay times. The crystal crack and inclusion problems were discussed and various precautions were taken to improve the crystalline quality. In all Dy3+: LuYAG crystals, absorption cross-section of each absorption band increases with an increment of Lu3+ content, and the strong absorption with a peak at 447 nm makes Dy3+: LuYAG as highly effective to be pumped by blue-emitting LDs (laser diodes). Under 447 nm excitation, strong yellow emissions (582 nm) were obtained, and in four samples Dy3+: Lu1.5Y1.5Al5O12 crystal shows an intense intensity in the yellow region. Decay times of Dy3+: 4F9/2 level increases with an increment of Lu3+ content. Comparison of mechanical and spectroscopic features revealed that the best candidate for achieving yellow lasing action was Dy3+: Lu1.5Y1.5Al5O12 crystal.

High‐Quality Bulk β‐Ga2O3 and β‐(AlxGa1−x)2O3 Crystals: Growth and Properties

A method for the growth of high‐quality gallium oxide (β‐Ga2O3) bulk crystals from the melt is developed. The influence of the atmosphere in the process zone on the stability of growth and the quality of Czochralski grown crystals is studied. The structural properties of the crystals obtained are investigated. Samples of gallium oxide substrates are demonstrated. The possibility of growing bulk crystals of solid‐solution oxides (AlxGa1–x)2O3 is tested.

Bulk crystal growth, crystalline perfection and optical homogeneities of 2AP4N single crystals for second and third order frequency conversion and terahertz (THz) device applications

Bulk size organic 2AP4N single crystals were grown by a point seed rotation technique using methanol solvent. The lattice dimensions of the grown crystal and their various crystalline planes have been analyzed by XRD measurement and also the lattice strain was calculated. The lattice perfection was examined by HRXRD and found to be extremely good. The optical transparency and cut-off value of the grown crystal were analyzed by the UV–Vis NIR measurement. The crystalline homogeneity has been confirmed by the birefringence and Mach-Zehnder interferometry techniques. The SHG measurement has been carried out with different particles. The refractive indices of grown crystal have been measured in different wavelengths by prism coupling technique and the Sellmeier's co-efficient has been calculated. The Type-I and Type-II phase-matching angles were determined and the crystal was cut along the phase-matching angles. The third order nonlinear optical parameters were analyzed by Z-scan technique. In addition, the crystal shows potential to generate pulsed Terahertz (THz) radiation by optical rectification using 800 nm wavelength at 140 fs, obtained from Ti: Sapphire Laser. The generated THz spectrum is extended up to 3.0 THz. The maximum conversion efficiency of the generated signal is of the order of 0.64 × 10 −5 %. •Optically high quality with bulk size single crystal was grown by seed rotation technique •The grown crystal has high optical homogeneities and crystalline perfection •SHG efficiency is 4.5 times that of KDP material •Type-I and Type-II phase matching elements have been made •Third-order nonlinear susceptibility ‘ χ (3) ’ is 8.68 × 10 −8 esu. •The maximum conversion efficiency of the generated THz signal is 0.64 × 10 −5 %.

Melt Growth and Physical Properties of Bulk LaInO3 Single Crystals

Large bulk LaInO3 single crystals are grown from the melt contained within iridium crucibles by the vertical gradient freeze (VGF) method. The obtained crystals are undoped or intentionally doped with Ba or Ce, and enabled wafer fabrication of size 10 × 10 mm2. High melting point of LaInO3 (≈1880 °C) and thermal instability at high temperatures require specific conditions for bulk crystal growth. The crystals do not undergo any phase transition up to 1300 °C, above which a noticeable thermal decomposition takes place. The good structural quality of the crystals makes them suitable for epitaxy. The onset of strong optical absorption shows orientation‐dependent behavior due to the orthorhombic symmetry of the LaInO3 crystals. Assuming direct transitions, optical bandgaps of 4.35 and 4.39 eV are obtained for polarizations along the [010] and the [100], [001] crystallographic directions, respectively. There is an additional weak absorption in the range between 2.8 and 4 eV due to oxygen vacancies. Density‐functional‐theory calculations support the interpretation of the optical absorption data. Cathodoluminescence spectra show a broad, structured emission band peaking at ≈2.2 eV. All bulk crystals are electrically insulating. The relative static dielectric constant is determined at a value of 24.6 along the [001] direction.