II-VI Semiconductor Research Articles

Atomic Sulfur Passivation Improves the Photoelectrochemical Performance of ZnSe Nanorods.

We introduced atomic sulfur passivation to tune the surface sites of heavy metal-free ZnSe nanorods, with a Zn2+-rich termination surface, which are initially capped with organic ligands and under-coordinated with Se. The S2− ions from a sodium sulfide solution were used to partially substitute a 3-mercaptopropionic acid ligand, and to combine with under-coordinated Zn termination atoms to form a ZnS monolayer on the ZnSe surface. This treatment removed the surface traps from the ZnSe nanorods, and passivated defects formed during the previous ligand exchange process, without sacrificing the efficient hole transfer. As a result, without using any co-catalysts, the atomic sulfur passivation increased the photocurrent density of TiO2/ZnSe photoanodes from 273 to 325 μA/cm2. Notably, without using any sacrificial agents, the photocurrent density for sulfur-passivated TiO2/ZnSe nanorod-based photoanodes remained at almost 100% of its initial value after 300 s of continuous operation, while for the post-deposited ZnS passivation layer, or those based on ZnSe/ZnS core–shell nanorods, it declined by 28% and 25%, respectively. This work highlights the advantages of the proper passivation of II-VI semiconductor nanocrystals as an efficient approach to tackle the efficient charge transfer and stability of photoelectrochemical cells based thereon.

Virtual Special Issue Dedicated to the 10th International Conference on Materials for Advanced Technologies (ICMAT), Symposium C: Semiconductor Photonics

This Special Issue is associated with the 10th International Conference on Materials for Advanced Technologies (ICMAT), Symposium C: Semiconductor Photonics held on 23–28 June, 2019 at Marina Bay Sands in Singapore. Organised through the Materials Research Society of Singapore (MRS-S), ICMAT has been held since 2001 and has attracted strong interest amongst the global materials science and engineering research communities. The 10th conference in the ICMAT series attracted over 3,500 delegates with a number of keynote and plenary presentations notably including four Nobel Laureates in Physics and Chemistry. The ICMAT conference consists of a number of topical symposia. Symposium C was organized jointly with Australian MRS and co-chaired by Professors Dao-Hua Zhang (NTU, Singapore), Chennupati Jagadish (ANU, Australia), Stephen J. Sweeney (University of Surrey, UK), Boon S. Ooi (KAUST, Saudi Arabia), Hao Gong (NUS, Singapore) and Weijun Fan (NTU, Singapore). The Symposium focused on recent developments in materials for applications in photonic devices covering systems including III-V and II-VI semiconductors, group IV alloys for silicon compatibility, oxides and perovskites for solar cell and emitter applications, quantum dot based devices and in general a wide variety of organic and inorganic materials spanning applications from the ultra-violet through to the mid-infrared. In total, 20 invited and 53 oral and 19 poster papers were presented over the four days of technical sessions.

In English

One of the promising materials for the development of 2D photonic structures is macroporous silicon obtained using photoanodic etching. Presence of periodically located cylindrical pores divided by silicon columns provides large effective surface of samples and enhanced optical and photo-physical characteristics of macroporous silicon structures. In this paper, the near-IR light absorption oscillations of 2D macroporous silicon structures with microporous silicon layers, SiO 2 nanocoatings and CdTe, ZnO surface nanocrystals are studded taking into account the Wannier–Stark electro-optical effect. An analysis of the experimental absorption spectra was carried out within the model of the resonant electron scattering with infinite amplitude on impurity states in strong electric field, with difference between two resonant energies equaled to the step of Wannier–Stark ladder. The constant oscillation period specifies the realization of Wannier–Stark effect on the randomly distributed surface bonds on silicon-nanocoating interface. We compared the IR absorption oscillations in 2D macroporous silicon with surface nanocoatings, analyzed shifts and deviations of oscillation peaks. The coherence of the IR spectra oscillations increases with the decrease of surface state concentration and with the optimal area of contact of nanocrystals to the macropore surface. Thus, the shift of oscillations for ZnO nanoparticles with optimal size of nanocrystals (3.7–4.4 nm) leads to deviations of the oscillation peaks within 0.26–0.42 meV, the oscillation coherence reaches 0.25–0.4 %. The small broadening parameter of the Wannier–Stark ladder levels G = 0.3¸0.8 cm –1 equals to that for surface phonon polaritons measured in thin films of II-VI semiconductors. Controllability and coherence of the investigated system are determined by forming of coherent Wannier levels in a narrow triangular potential well formed by an electric field at the silicon-nanocoating interface. In addition, we have proposed a high coherent optical quantum computer based on the quantum Wannier-Stark electro-optical effect on a silicon matrix with macropores and a layer of nanocrystals on the macropore surface.

Manganese-Doping-Induced Quantum Confinement within Host Perovskite Nanocrystals through Ruddlesden-Popper Defects.

The concept of doping Mn2+ ions into II–VI semiconductor nanocrystals (NCs) was recently extended to perovskite NCs. To date, most studies on Mn2+ doped NCs focus on enhancing the emission related to the Mn2+ dopant via an energy transfer mechanism. Herein, we found that the doping of Mn2+ ions into CsPbCl3 NCs not only results in a Mn2+‐related orange emission, but also strongly influences the excitonic properties of the host NCs. We observe for the first time that Mn2+ doping leads to the formation of Ruddlesden–Popper (R.P.) defects and thus induces quantum confinement within the host NCs. We find that a slight doping with Mn2+ ions improves the size distribution of the NCs, which results in a prominent excitonic peak. However, with increasing the Mn2+ concentration, the number of R.P. planes increases leading to smaller single‐crystal domains. The thus enhanced confinement and crystal inhomogeneity cause a gradual blue shift and broadening of the excitonic transition, respectively.

Mechanism of Mn emission: Energy transfer vs charge transfer dynamics in Mn-doped quantum dots

In the quest for new functional materials, transition metal doping in semiconductors has attracted significant attention, wherein introduction of dopant atoms alters a range of physical properties of the host such as its optical, magnetic, and electronic properties. Hence, the choice of appropriate dopants to meet the current challenges makes semiconductor doping a highly versatile field. In the past, Mn doping in II-VI semiconductors has been extensively studied. The interest in these systems arises from a prominent orange emission from an optically forbidden state. An extended debate in the literature spanning the last three decades has so far shed light on various anomalous properties of Mn emission, specifically in quantum-confined systems leading to more questions. In this perspective, we review the literature with specific emphasis on the mechanism of Mn emission and an understanding of the electron–hole pathway during the excitation and de-excitation process in doped quantum dots. We explore various phenomena of energy and charge transfer mechanisms along with experiments in support of these phenomena which can eventually lead to a better understanding of spin driven optoelectronics.

The History of the German Association for Crystal Growth

The History of the German Association for Crystal Growth

Structural quality in single crystalline CdSe ingots grown by PVT

CdSe is II-VI semiconductor with compact hexagonal structure. It has a band gap of 1.82 eV and a high stopping power for nuclear radiation. Single crystalline CdSe ingots were grown by Physical Vapor Transport (PVT) employing a horizontal reactor. As devices critically depend on material properties its single crystalline quality was determined by chemical etching and transmission electron microscopy. Results were compared to those corresponding to Bridgman High Pressure (HPB) grown material and also to PVT material grown in a vertical reactor. Keywords: Single crystalline CdSe ingots, PVT, HPB, Chemical etching, Optical Microscopy, Transmission and scanning electron microscopy.

Research progress of stability of luminous lead halide perovskite nanocrystals

The lead halide perovskite nanocrystals (NCs) have become more ideal luminescent materials due to the excellent properties such as narrow emission linewidth, photoluminescence quantum yield (PLQY), adjustable spectrum and facile preparation in comparison with traditional II-VI or III-V group semiconductor NCs. Until now, the external quantum efficiency (EQE) of light-emitting diode (LED) devices using perovskite NCs as emitting layers, has reached > 20%. This optical performance is close to that of the commercially available organic LED, which shows their great potential applications in solid state lighting and panel displaying. However, when perovskite NCs suffer light, heat and polar solvent, they exhibit the poor stability owing to the intrinsic ion properties of perovskite, and highly dynamic interface between NCs and ligands as well as the abundant defects on the surface of NCs. Therefore, how to elevate their stability is a key and urgent problem. In this review, three methods to improve the stability of NCs are summarized: 1) <i>I</i><i>n situ</i> surface passivation with tight-binding or protonation-free sole ligands such as oleic acid (OA), oleamine (OAM), dodecyl benzene sulfonic acid, octylphosphonic acid, sulfobetaines, lecithin and two ligands such as 2-hexyldecanoic acid/OAM, bis-(2,2,4-trimethylpentyl)phosphinic acid/OAM as well as three ligands such as OA/OAM/Al(NO<sub>3</sub>)<sub>3</sub>·9H<sub>2</sub>O, OA/OAM/tris(diethylamino)phosphine); the postsynthetic ligand exchange or passivation with 1-tetradecyl-3-methylimidazolium bromide, 2-aminoethanethiol, silver-trioctylphosphine complex and n-dodecylammonium thiocyanate; 2) the doping of Cs<sup>+</sup> by FA<sup>+</sup>, Na<sup>+</sup> and the doping of Pb<sup>2+</sup> by Zn<sup>2+</sup>, Mn<sup>2+</sup>, Cd<sup>2+</sup>, Sr<sup>2+</sup>, Sb<sup>3+</sup> in perovskite NCs; 3) the surface coating with inorganic oxides (SiO<sub>2</sub>, ZrO<sub>2</sub>, Al<sub>2</sub>O<sub>3</sub>, NiO<i><sub>x</sub></i>), inorganic salts (NaNO<sub>3</sub>, NH<sub>4</sub>Br, PbSO<sub>4</sub>, NaBr, RbBr, PbBr(OH)), porous materials (mesoporous silica, zeolite-Y, lead-based metal-organic frameworks), polymer materials (polystyrene, poly(styrene-ethylene-butylene-styrene, poly(laurylmethacrylate), poly(maleic anhydride-alt-1-octadecene), polyimide, poly(n-butyl methacrylate-co-2-(methacryloyloxy)ethyl-sulfobetaine)). Besides, we make some suggestions to further improve the stability of NCs as follows: 1) Developing the surface ligands with good dispersity and multi-coordination groups; 2) theoretically studying the influence of ion doping on the structure and stability; 3) realizing the stable and conductive metal oxides shell for uniform and compact encapsulation of NCs core. In a word, these conventional methods can enhance the stability of NCs to a certain extent, which fail to meet the requirements for practical application, so more efforts will be needed in the future.

Advances in improved photoluminescence properties of all inorganic perovskite nanocrystals via metal-ion doping

Metal halide perovskite nanocrystals (NCs) have attracted great attention in the fields of light-emitting diodes, lasers, X-ray imaging, solar cells and photoelectric detectors due to their excellent optoelectronic properties. Compared with organic-inorganic hybrid perovskite NCs, all inorganic perovskite CsPb<i>X</i><sub>3</sub> (<i>X</i> = Cl, Br, I) NCs have good photoelectric properties and high stability. To further improve the photoluminescence (PL) quantum yields (QYs) and stability of CsPb<i>X</i><sub>3</sub> NCs, researchers reduced the defects as nonradiative recombination centers in NCs by the following strategies: 1) surface treatment with different ligands; 2) control of synthesis conditions with halide rich compounds; 3) doping of metal ions. Among them, metal doping is considered as a universal and effective way to adjust the optoelectronic properties of semiconductors. It is found that the type and the concentration of metal ions have great influence on the electronic band structure and PL performance of NCs after the metal ions have been doped into CsPb<i>X</i><sub>3</sub> NCs. At the same time, compared with II-VI and III-V semiconductors, the unique structure of all inorganic perovskite NCs makes the doping of metal ions easier. Appropriate doping can not only enhance the intrinsic optical properties of the NCs without affecting their crystal structure, but also introduce new electronic energy levels into the NCs and new luminescent properties of doped metal ions. Based on metal ions doping strategy, the PLQYs of doped CsPb<i>X</i><sub>3</sub> NCs have been enhanced to nearly 100%. In this work, we summarize recent advances in metal doping of the four typical kinds of perovskite NCs, including CsPbCl<sub>3</sub>, CsPbBr<sub>3</sub>, CsPbI<sub>3</sub>, and Mn<sup>2+</sup> doped CsPb<i>X</i><sub>3</sub>, and discuss the physical mechanisms of the improved properties through doping metal ions. It should be pointed out that the doping of some metal ions such as Ni<sup>2+</sup> and Cd<sup>2+</sup> into the above four kinds of NC systems can effectively passivate NC defects, thus improving the PL QY and stability of NCs. In addition, we put forward some personal perspectives on the future research subjects of interest and directions of metal doping for enhanced PL of CsPb<i>X</i><sub>3</sub> NCs, which needs to be further explored in order to promote extensive application of perovskite NCs to various optoelectronic devices.

Charge accumulation resulting in metallization of II-VI semiconductor (ZnX X = O, S, Se) films neighboring polar liquid crystal molecules and their surface plasmonic response in the visible region.

The surfaces of some IIB-VI semiconductors (ZnX, X = O, S, Se) are metallized by neighboring highly polar and atomically vertically aligned (VA) liquid crystal (LC) molecules. Owing to polar catastrophe, the charge carriers swarm in an extremely thin layer and the density can achieve 4.86 × 1028 m-3 close to the LC layer, which can be regarded as a 2-dimensional electron gas (2DEG). Using density functional theory (DFT), it was found that the dielectric functions of the modified layer become negative in the visible region. This indicates the semiconductor/LC platform is an ideal active plasmonic candidate, apart from the lossy metal constituents. Experimentally, after mediation with phase gratings written in the LC system, surface plasmon polaritons (SPPs) can be excited at the semiconductor surface and localized charges are gathered in an adjacent LC layer. With the help of the enhanced static electric field from the metallic surface, significantly more 2D diffraction orders in many rows and columns and a huge energy transfer between the laser beams and SPPs was observed, which is consistent with the metallization results and the bidirectional coupling between the SPPs and incident lights. The generalization of the II-VI semiconductors means the system has great promise for use in practical applications owing to the ultra-low loss. The novel insights regarding this combination with liquid crystals will be beneficial for real-time holographic displays and the study of tunable epsilon near zero points.

Fabrication and properties of non-balance electric bridge gas sensor based on a single Sb doped ZnO microwire

Zinc oxide (ZnO) is a wide direct band gap (3.37 eV) II-VI semiconductor material with a wide range of applications in light emitting devices, solar cells, field emission devices, gas sensors, etc. Over the past decades, metal oxide semiconductors have been investigated extensively for sensing various types of vapors and toxic gases. Among the various metal oxides for gas sensing applications, ZnO is one of the potential materials for high response, stability and sensitivity to volatile organic gases. At present, the ZnO-based gas sensor has a relatively high operating temperature. However, the stability and lifetime of gas sensors operating under high temperature conditions with a long term will be greatly reduced. In addition, the power consumption of gas sensors is also significantly increased. Furthermore, there can exist the potential of explosion when gas sensors are used to detect the flammable gases at high temperature. Therefore, it is necessary to improve the sensing properties and reduce the operating temperature of gas sensors. In this paper, ultra-long, large-sized Sb doped ZnO microwires are successfully prepared by using chemical vapor deposition. The gas sensor is based on the principle of non-balance electric bridge, and a single Sb doped ZnO microwire is used as a bridge arm <i>R</i><sub>4</sub> of non-balance electric bridge to produce a gas sensor that can work at room temperature. The results show that the response-recovery curves of sensors at the acetone and ethanol concentrations of 20 ppm, 50 ppm, 100 ppm and 200 ppm (1 ppm = 10<sup>–6</sup>) are rectangular at room temperature, and have stable current values in air and measured gas, and the response value of the device gradually increases with gas concentration increasing. Furthermore, the detection of acetone and ethanol gas reveal that the device has better selectivity for acetone gas. The response of the gas sensor to 200 ppm acetone is about 243%, with response and recovery time of 0.2 s and 0.3 s, respectively. Compared with the traditional resistive gas sensor, this non-balanced electric bridge sensor has high response, fast response and recovery time. In addition, the sensing mechanism of the device is also studied.

О доминирующем механизме безызлучательного возбуждения ионов марганца в II-VI полумагнитных полупроводниках

Doping of group II-VI semiconductors and low-dimensional structures based on them with manganese leads to effective quenching of electro-and photoluminescence provided that the electron excitation energy of the crystal exceeds the energy of the intracenter transition of Mn2+ EMn и 2.1 eV. Quenching involves efficient energy transfer from the photoexcited crystal to Mn2 + ions. There are three possible mechanisms of this non-radiative energy transfer: dipole-dipole, exchange and related mechanism associated with sp-d mixing. Although the dipole-dipole mechanism is thought to be ineffective due to the forbidden intracenter transition in Mn2+, and the spin-dependent exchange mechanism is dominant, not all experimental facts accumulated to date supports this conclusion. The article discusses two experimental approaches to identify the dominant mechanism of energy transfer to Mn2 + ions and to evaluate the partial contributions of the mechanisms. One of these approaches is related to optically detectable magnetic resonance at single diluted magnetic semiconductor quantum dots (QD), the second - to plasmon amplification of energy transfer to Mn2 + ions by means of dipole-dipole interaction.

Impact of transition metal ion doping on electron spin relaxation time in CdSe/ZnSe quantum dots

Theoretical calculations of spin relaxation time (SRT) of conduction electrons have been carried out considering the relaxation mediated by acoustic phonons using k.p perturbation theory and envelope function approximation in a transition metal doped II-VI semiconductor quantum dot under the strong confinement regime. In this calculation, we are considering the transitions in the Zeeman sublevels arising due to magnetic impurity doping and applied magnetic field in a Mn doped CdSe/ZnSe quantum dots. The occurrence of spin polarization switching at moderately low applied magnetic field is established in Cd1−xMnxSe/ZnSe quantum dots. The spin relaxation times have been found to be considerably longer with a higher dopant concentration in small magnetic fields (B < 2T) and at very low temperature (T < 50 K) regime. The results may help to demonstrate that, such small quantum dots can successfully be used as polarization switch in different spintronic nano-device.

Optical properties of pure and doped CdS nanoparticles under solvothermal method

The synthesis of CdS nano particles have been widely studied for their potential usage in the field of optics. The Semi conductor nanoparticles doped with transition metal ions have attracted a wide attention due to their excellent luminescent properties. The transition metal doped nano particles have different optical properties corresponding to their host counter parts. These nano particles have tremendous applications in the fabrication of optical light emitting diodes and to design a suitable window material in fabrication for solar cells. The microwave assisted solvothermal method is used to prepare the nano particles in this study. The nano structured materials of CdS were characterized by XRD and UV techniques. The size of the crystallite is determined by XRD to be 18.26 nm depending on the amount of the molar ratio of the reactants present in the sample. The nanocrystalline nature of CdS particles and the diffused pattern shows the presence of hexagonal phase in the present system. The quantum size dependent effect and the optical quality of the CdS and Mn-doped CdS are studied. The optical absorption and transmitance spectrum of the Pure and Mn-doped CdS nanocrystals are synthesized in this work. CdS is a commercially important II-VI semiconductor having wide optical band gap, rendering it a very attractive material for optical application especially in nanocrystalline form. The UV-absorption edge provides a reliable estimate of the band gap of any system. It is found that the band gap of the pure CdS nanosystem in the present study is 2.45 eV and this value is found to be larger than that of bulk CdS. This variation of the band gap may be useful to design a suitable window material in fabrication for solar cells. In optoelectronics, it finds use as light emitting diode, reflector, dielectric filter and window material.

Investigation of Structural Properties of a Ternary Semiconductor Compound SrxCd1-xO (x= 0.00, 0.25, 0.50, 0.75 and 1.00)

The present work is based upon the investigation of structural properties of technologically important compound SrxCd1-xO (x= 0.00, 0.25, 0.50, 0.75 and 1.00) of group II-VI semiconductors. The Linear Combination of Atomic Orbital method has been used within density functional theory as embodied in CRYSTAL code. The Hybrid scheme B3LYP is used for making the Kohn-Sham Hamiltonian. The effect of the composition on lattice constant, bulk modulus is investigated. The deviations of the lattice constant from the Vegard’s law were observed for three cases

Optical Properties Study of II-VI Semiconductors NPs Prepared by Laser Ablation in Liquid Technique

Optical Properties Study of II-VI Semiconductors NPs Prepared by Laser Ablation in Liquid Technique

Synchrotron Deep-UV Photoluminescence Imaging for the Submicrometer Analysis of Chemically Altered Zinc White Oil Paints.

Zinc oxide (ZnO) is a II-VI semiconductor that has been used for the last 150 years as an artists' pigment under the name of zinc white. Oil paints containing zinc white are known to be prone to the formation of zinc carboxylates, which can cause protrusions and mechanical failure. In this article, it is demonstrated how a multispectral synchrotron-based deep-UV photoluminescence microimaging technique can be used to show the distribution of zinc soaps on the submicrometer scale and how this information is used to further the understanding of zinc white degradation processes in oil paint. The technique is based on the luminescence of zinc soaps in the near-UV (∼3.65 eV) upon excitation in the deep-UV (4.51 eV), involving transitions that are argued to subsequently involve ligand-to-metal and metal-to-ligand charge transfer with intermediate structural reconfiguration. Because the primary emission peak lies at a higher energy than the band gap of ZnO (3.3 eV), the signal can easily be isolated from the pigment's very intense band gap and trap state emission by employing a multispectral acquisition approach. Moreover, analysis at such short wavelengths, in combination with a UV-transparent optical setup, allows for lateral resolution on the order of 200 nm to be obtained. The unprecedented capabilities of the microimaging technique are illustrated by showing its application to the study of a historical cross section from an early 20th century painting by Piet Mondrian. Revealing the submicrometer distribution of crystalline zinc soaps in this cross section provides new insights that suggest that microfissures, the starting points of paint delamination, are the result of an overall expansion of a heavily saponified zinc white layer.

Exciton-optical phonon coupling in II-VI semiconductor nanocrystals.

This perspective reviews the topic of exciton-phonon coupling (EPC) in II-VI semiconductor nanocrystals. First, EPC is defined and its relevance is discussed, both as it influences the properties of the materials relevant to applications and as a probe of electronic structure. Different experimental and theoretical methods for probing EPC are outlined. Results for several different classes of II-VI nanocrystals are summarized. Finally, possible future directions are outlined.

Гидрохимический синтез халькогенидов металлов. Часть 41. Гидрохимическое осаждение тонких пленок селенида кадмия селеносульфатом натрия

The group II-VI semiconductor materials including Cadmium Selenide (CdSe) thin films are widely used in many fields of science and technology, in particular in optoelectronics, nanoelectronics and solar energy. Chemical bath deposition (CBD) represents the simplest and the most available technique for deposition of semiconducting layers. CBD is characterized by deletion of toxic gaseous precursors, operation at low temperature and using of inexpensive equipment. The ionic equilibriums in reaction mixture «CdCl2 – L − Na2SeSO3» (L− NH4OH or Na3C6H5¬O7 or mixture of NH4OH and Na3C6H5¬O7 ) were calculated in present work. The prevailing cadmium complex compounds were determined in appropriate for CBD of cadmium selenide films pH range. The main complex compounds inhibiting fast formation of cadmium selenide are Cd(OH)Cit^(2-) complex (in citrat- and ammonia-citrat mixtures) and 〖Cd(NH_3)〗_5^(2+) complex (in ammonia mixture). Also the boundary conditions of forming CdSe and Cd(OH)2 in reaction mixture were determined by thermodynamic calculation based on crystallization factor to estimate the formation conditions of main (CdSe) and impurity (Cd(OH)2) phases. The results of the calculations show that the solid phase of cadmium selenide is possible to form in pH range from 10 to 14. CdSe films were grown by chemical bath deposition on glass substrates at a temperature of 353 K. The thickness of films ranges from 100 to 220 nm. The grain size of films is about 30 nm which was determined by electron microscopic investigations. The elemental composition of cadmium selenide was defined by energy dispersive analysis; the ratio of cadmium and selenium is 1.03 : 1.16. The conductivity of n-type was determined by the sign of thermoelectromotive force.

Symmetry-Protected Ideal Type-II Weyl Phonons in CdTe.

Nontrivial low-energy excitations of crystalline solids have insightfully strengthened understanding of elementary particles in quantum field theory. Usually, topological quasiparticles are mainly focused on fermions in topological semimetals. We alternatively show by first-principles calculations and symmetry analysis that ideal type-II Weyl phonons are present in zinc-blende cadmium telluride, a well-known II-VI semiconductor. Importantly, these type-II Weyl phonons originate from the inversion between the longitudinal acoustic and transverse optical branches. Symmetry guarantees that the type-II Weyl points lie along the high-symmetry lines at the boundaries of the Brillouin zone even with a breaking of inversion symmetry, exhibiting the robustness of protected phonon features. The nontrivial phonon surface states and surface arcs projected on the semifinite (001) and (111) surfaces are investigated. The phonon surface arcs connecting the Weyl points with opposite chirality, guaranteed to be very long, are clearly visible. We not only offer a promising candidate for studying type-II Weyl phonons but also provide a route to realize symmetry-protected nontrivial phonons and related applications in realistic materials.