Deren Yang

Zhejiang University | ZJU · State Key Lab of Silicon Materials and School of Materials Science and Engineering

Increasing the diameter and reducing the dislocation density of 4H silicon carbide (4H-SiC) single crystals are the development tendency of 4H-SiC single-crystal substrate to reduce the cost of 4H-SiC based devices. In this work, we use the growth of a 100 mm 4H-SiC single crystal as an example to demonstrate that the tiling approach is attractive...

The pressure-dependent lattice dynamics of 4H-SiC is investigated using diamond anvil cell, and compared with those of 3C- and 6H-SiC. It is found that both the zone-center longitudinal optical (LO) and transverse optical (TO) modes shift to higher frequencies with the increase of the applied pressures. This indicates that polymorph transitions are...

Due to its intriguingly electrical, thermal and optical characteristics, single-crystal silicon carbide (SiC), one of the most significant wide-bandgap semiconductors, has been receiving intense attention. Up to date, SiC has been investigated for applications in high-power and high-frequency electronics, ultraviolet optoelectronics and quantum com...

Developing a low-cost, room-temperature operated and complementary metal-oxide-semiconductor (CMOS) compatible near infrared silicon photodetector is of interest for creating all-silicon optoelectronic integrated circuits. However, a silicon-based photodetector usually cannot respond to infrared light with wavelengths longer than 1100 nm, due to th...

High-purity semi-insulating (HPSI) 4H silicon carbide (4H-SiC) single crystals are critical semiconductor materials for fabricating GaN-based high-frequency devices. One of the major challenges for the growth of HPSI 4H-SiC single crystals is the unintentional doping of nitrogen (N) and boron (B). The addition of hydrogen has been supposed to mitig...

In this work, we propose to reveal the subsurface damage (SSD) of 4H-SiC wafers by photo-chemical etching and identify the nature of SSD by molten-alkali etching. Under UV illumination, SSD acts as a photoluminescence-black defect. The selective photo-chemical etching reveals SSD as the ridge-like defect. It is found that the ridge-like SSD is stil...

In this work, the anisotropic deformation and anisotropic mechanical properties of 4H silicon carbide (4H-SiC) single crystal wafers are proposed using nanoindentation. The C face of 4H-SiC wafer shows higher hardness and lower fracture toughness than those of the Si face. Because the deformation of 4H-SiC is assisted by the nucleation and slip of...

Herein, the surface passivation quality of p‐type boron‐doped Czochralski silicon (Cz‐Si) wafers with passivated emitter and rear cell (PERC) structure during 200 °C dark annealing is investigated. During such a treatment, a reduction in the saturation current density (J 0) along with the degradation and regeneration of minority carrier lifetime ca...

We report on the visible and near-infrared electroluminescence (EL) from the light-emitting device (LED) based on the erbium (Er)-doped ZnO (ZnO:Er)/SiO2/n+-Si heterostructure, wherein an ∼10 nm thick SiO2 intermediate layer serves as the energy plateau for producing hot electrons, which come from n+-Si via the trap-assisted tunneling mechanism. Th...

Treating hazardous waste Ni from the electroplating industry is mandated world-wide, is exceptionally expensive, and carries a very high CO2 footprint. Rather than regarding Ni as a disposable waste, the chemicals and petrochemicals industries could instead consider it a huge resource. In the work described herein, we present a strategy for upcycli...

Crystalline silicon solar cells are always moving towards “high efficiency and low cost”, which requires continuously improving the quality of crystalline silicon materials. Nevertheless, crystalline silicon materials typically contain various kinds of impurities and defects, which act as carrier recombination centers. Therefore these impurities an...

To meet a growing demand for information processing, brain-inspired neuromorphic devices have been intensively studied in recent years. As an important type of neuromorphic device, synaptic devices have attracted strong attention. Among all the kinds of materials explored for the fabrication of synaptic devices, semiconductor nanocrystals (NCs) hav...

Silicon is vital for its high abundance, vast production, and perfect compatibility with the well-established CMOS processing industry. Recently, artificially stacked layered 2D structures have gained tremendous attention via fine-tuning properties for electronic devices. This article presents neuromorphic devices based on silicon nanosheets that a...

Strong sub-bandgap absorption of hyperdoped silicon caused by an impurity deep band has attracted a lot of interest in recent years, which is promising for photodetector application. Currently, the responsivity of hyperdoped Si photoconductors is still low due to the carrier scattering by hyperdoping induced defects, which impedes their application...

Cast monocrystalline silicon is a high-quality photovoltaic material with low fabrication cost, the developing trend is to increase quality stability. This work focuses on solving the edge multicrystalline region and related defects. By setting the modified seeds using Siemens polycrystalline raw silicon at the ingot edges, high-quality cast monocr...

Hyperdoping that introduces impurities with concentrations exceeding their equilibrium solubility has been attracting great interest since the tuning of semiconductor properties increasingly relies on extreme measures. In this review we focus on hyperdoped silicon (Si) by introducing methods used for the hyperdoping of Si such as ion implantation a...

Tandem Solar Cells Light‐induced phase segregation is the chief culprit for the open‐circuit voltage deficit and photo‐instability in mix‐halide perovskite solar cells with wide‐bandgap. In article number 2203319, Xuegong Yu and co‐workers report a highly efficient and photo‐stable wide‐bandgap perovskite solar cell with a top‐ranking open‐circuit...

Vacuum vapor deposition (VVD) is a promising way to advancing the commercialization of perovskite light sources owing to its convenience for wafer‐scale mass production and compatibility with silicon photonics manufacturing infrastructure. However, the light emission performance of VVD‐grown perovskites still lags far behind that of the conventiona...

Combining the core-shell structure with the optimization of surface composition and structure in the shell is a fantastic strategy to enhance the electrocatalytic performances. Here, we synthesized trimetallic Au@Pt x Sn y core-shell nanoparticles (NPs) with tunable composition and structure of Pt-Sn alloyed shells. Impressively, the Au@PtSn core-s...

Hydrogenated graphene is easy to prepare and chemically stable. Besides, hydrogenation of graphene can open the band gap, which is vital for electronic and optoelectronic applications. Graphene/Si Photodetector (PD) has been widely studied in imaging, telecommunications, and other fields. The direct contact between graphene and Si can form a Schott...

Wide-bandgap (WBG) perovskite solar cells (PSCs) with high performance and stability are in considerable demand in the photovoltaic market to boost tandem solar cell efficiencies. Perovskite bandgap broadening results in a high barrier for enhancing the efficiency of the PSCs and causes phase segregation in perovskite. In this study, we show that t...

Owning to the superior properties of the wide bandgap, high carrier mobility, high thermal conductivity and high stability, 4H silicon carbide (4H-SiC) holds great promise for the applications of electrical vehicles, 5G communications and new-energy systems. Although the industrialization of 150 mm 4H-SiC substrates and epitaxial layers has been su...

Ion migration is regarded as the chief culprit for the long-term instability in perovskite solar cells (PSCs), and iodine ions are the most subjects to migration in PSCs. Strategies, such as grain size engineering, chemical bonding engineering, steric impediment effect, and interface passivation, are employed to suppress the iodine migration but un...

Cast-mono silicon (CM-Si) is a promising method to fabricate cost-effective photovoltaic silicon wafers, and dislocation clusters are currently one of the most detrimental defects in CM-Si. Once formed, they propagate rapidly and unlimitedly in the single crystalline lattice and then serve as strong recombination centers and shunts in solar cells,...

Cast‐mono silicon (CM‐Si) is a promising substrate to fabricate cost‐effective photovoltaic wafers used for solar cells with higher efficiency compared with conventional cast multi‐crystalline silicon (mc‐Si) due to its high throughput and good ingot quality. However, the unavoidable appearance of defects like dislocation, sub‐grain boundaries (sub...

Wide‐bandgap perovskite solar cells (PSCs) with an optimal bandgap between 1.7 and 1.8 eV are critical to realize highly efficient and cost‐competitive silicon tandem solar cells (TSCs). However, such wide‐bandgap PSCs easily suffer from phase segregation, leading to performance degradation under operation. Here, it is evident that ammonium diethyl...

Floating particles often appear during the Czochralski (CZ) growth of β-Ga2O3 in the Ir crucible, thereby impeding the seeding process. Identifying the floating nanoparticles and then inhibiting or removing them is critical for growing high-quality β-Ga2O3 single crystals. We grew β-Ga2O3 crystals containing floating particles using the CZ method....

As a semiconductor with a wide bandgap, 4H silicon carbide (4H-SiC) has considerable potential for high-temperature and high-power devices. It is widely established that p-type 4H-SiC is formed predominantly by doping Al. Although Al diffusion in 4H-SiC is often negligible at low temperatures due to the tight bonding of Al in 4H-SiC, the diffusion...

Silicon heterojunction (SHJ) solar cells have garnered significant attention recently due to their excellent performance, benefiting from the outstanding passivation quality of intrinsic/doped hydrogenated amorphous silicon (a‐Si:H) bilayers. In this paper, we find that current injection at elevated temperatures can enhance the electrical performan...

All-inorganic perovskites are considered as preferred materials for next-generation X-ray detectors. However, preparing high-quality thick films by traditional solution-based methods remains challenging due to the low solubility of the precursors. In this work, chemical vapor deposition technology is employed to grow Si-based all-inorganic cesium-l...

Silica (SiO2) has been widely used as a support for various heterogeneous catalysts because of its Earth abundance, low cost, and large specific surface area. Except for the families of mesoporous and microporous silica, ordinary silica has long been perceived as just an inert support for better dispersion and mechanistic studies. However, recent a...

Oxygen precipitate-related defects in Czochralski silicon have been studied by electron-beam-induced current (EBIC) and deep-level transient spectroscopy (DLTS). The EBIC results present that oxygen precipitates combined with dislocations can strengthen carrier recombination. The DLTS data reveals two levels of T1 (Ev+0.43 eV) and T2 (Ev+0.26 eV),...

Basal plane dislocations (BPDs) are one of the most harmful dislocations in 4H silicon carbide (4H-SiC). Understanding the nucleation of BPDs is the basis of reducing the density of BPDs in 4H-SiC. In this work, we investigate the nucleation mechanism of BPDs, as well as the effect of doping on the nucleation of BPDs in 4H-SiC using nanoindentation...

One of the major challenges of 4H-silicon carbide (4H-SiC) is that the preparation of low resistivity p-type 4H-SiC single crystals lags seriously behind that of low resistivity n-type 4H-SiC single crystals, hindering the development of important 4H-SiC power devices such as n-channel insulated gate bipolar transistors. In particular, the resistiv...

Basal-plane dislocations (BPDs) pose a great challenge to the reliability of bipolar power devices based on the 4H silicon carbide (4H-SiC). It is well established that heavy nitrogen (N) doping promotes the conversion of BPDs to threading edge dislocations (TEDs) and improves the reliability of 4H-SiC-based bipolar power devices. However, the inte...

Infrared photodetectors based on crystalline silicon has attracted much attention due to its low cost and good compatibility with complementary metal‐oxide‐semiconductor (CMOS) technology in ultra‐largescale integrated circuits (ULSI). However, silicon shows no response to infrared light with a wavelength over 1100 nm corresponding to its bandgap o...

For nitrogen-doped Czochralski (NCZ) silicon, it is well known that nitrogen (N) and oxygen (O) impurities can interact to form nitrogen–oxygen shallow thermal donors (N–O STDs); moreover, the N impurities can be involved into heterogeneous nucleation to facilitate the formation of grown-in oxide precipitates. However, how the N impurities particip...

Nonlinear optical (NLO) switch materials have attracted considerable attention in photonics. Although various materials based on complex structural transitions have been developed extensively, the studies on light‐driven up‐conversion laser switches are rare, which have advantages including easy operations at room temperature and high contrasts. He...

Resistivity tailing seriously reduces the production of phosphorus-doped n-type cast mono-like silicon (CM-Si) ingots and increases costs. However, it is believed that a uniform axial dopant profile can be efficiently obtained by adjusting furnace pressure to enhance phosphorus evaporation at the ingot top due to high saturated vapor pressure of ph...

Formate is considered as the most economically viable product of the prevalent electrochemical CO2 reduction (ECR) products. However, most of the catalysts for ECR to formate in aqueous solution often suffer from low activity and limited selectivity. Herein, we report a novel Ce-doped Bi2O3 nanosheet (NS) electrocatalyst by a facile solvothermal me...

Pd-based nanocatalysts are critical to the commercialization of direct ethanol fuel cells (DEFCs); however, the synthesis of Pd-based binary alloy nanocrystals with well-defined branches is still a great challenge. Here we report a facile seed-mediated approach for the synthesis of PdSn alloy octopods with precisely controlled branches and tunable...

Light soaking (LS) effect of perovskite solar cells (PSCs), i.e., the power conversion efficiency (PCE) increases under continuous light illumination (CLI), has attracted a lot of attention recently. Herein, it is reported that a strong LS effect occurs in the FAxMA1‐xPbI3 (FAMA) PSC for its PCE increases from 7.5% to 20.5% under CLI. Based on the...

Correction for ‘Interlayer exciton emission in a MoS 2 /VOPc inorganic/organic van der Waals heterostructure’ by Yuhan Kong et al. , Mater. Horiz. , 2022, DOI: 10.1039/d1mh01622a.

Recent progress in the synthesis and assembly of two-dimensional (2D) materials has laid the foundation for various applications of atomically thin layer films. These 2D materials possess rich and diverse properties such as layer-dependent band gaps, interesting spin degrees of freedom, and variable crystal structures. They exhibit broad applicatio...

Two-dimensional (2D) Transition Metal Chalcogenides (TMCs) have attracted tremendous interest from both the scientific and technological communities due to their variety of properties and superior tunability through layer number, composition, and interface engineering. Wafer-scale production of 2D TMCs is critical to the industrial applications of...

For Czochralski silicon (Cz-Si) solar cells, swirl-shaped regions in silicon wafers could lead to efficiency degradation, usually accompanied by hot spots and thermal breakdown. In this paper, comprehensive characterization methods including electroluminescence (EL), photo-induced current (LBIC), quantum efficiency (QE), cell efficiency, carrier li...

In this work, we demonstrate that the forward current injection together with annealing as pre-treatment can dramatically suppress Voc degradation in both p-type Cast-Mono silicon (CM-Si) and multicrystalline silicon (mc-Si) Passivated Emitter and Rear Cells (PERC) during the following prolonged Light and elevated Temperature Induced Degradation (L...

In our previous report, the erbium (Er)-related visible and near-infrared (NIR, ∼1.54 μm) electroluminescence (EL) from the light-emitting device (LED) with Er-doped TiO2 (TiO2:Er) film sputtered on the heavily boron-doped p-type silicon (p⁺-Si) substrate thus forming the so-called TiO2:Er/p⁺-Si heterostructure was realized. However, it is still a...

Stable Cu Catalysts In article number 2104972, Binhang Yan, Wei Sun, and co‐workers design a stable Cu/2DSiO2 catalyst with strong metal–support interaction for high‐temperature CO2 reduction. The “beads‐in‐a‐book” structure is derived through growth of Cu between 2D Si nanosheets. The authors believe that this work could stimulate more interest in...

Basal plane dislocations (BPDs) pose great challenge to the reliabilities of 4H silicon carbide (4H-SiC) based bipolar power devices. It is well established that heavy nitrogen (N) doping promotes the conversion of BPDs to threading edge dislocations (TEDs) and improves the reliability of 4H-SiC based bipolar devices. However, the interaction betwe...

Self-powered perovskite X-ray detectors have drawn increasing attention due to the merits of low noise, low power consumption as well as high portability and adaptability. However, the active layer thickness is usually compromised by the small carrier diffusion length, which leads to inefficient X-ray attenuation and hence low sensitivity of the de...

PtRu/C is a well-known commercial electrocatalyst with promising performance for the methanol oxidation reaction (MOR). Further improving the MOR properties of PtRu-based electrocatalysts is highly desirable, especially through structure design. Here we report a facile approach for the synthesis of PdPtRu nanocages with different components through...

Metal halide perovskites (MHPs) have emerged as promising X‐ray detection materials. However, most MHP‐based X‐ray detectors are incompatible for large‐area preparation and integration, and suffer from the serious ion migration issue. This work demonstrates a “perovskite‐in‐a‐host” nanocomposite structure for X‐ray detection, by embedding the perov...

Recent progress in the synthesis and assembly of two-dimensional (2D) materials has laid the foundation for various applications of atomically thin layer films. These 2D materials possess rich and diverse properties such as layer-dependent band gaps, interesting spin degrees of freedom, and variable crystal structures. They exhibit broad applicatio...

G8 ingots have a significant advantage in production capacity and yield improvement for directional solidification silicon. To improve the uniformity of the 3D solid/liquid (S/L) interface at the periphery of the G8 ingots, we developed a new structure for side heater that installs six electrodes compared to three in convectional AC heaters. A near...

Cu‐based catalysts exhibit excellent performance in hydrogenation reactions. However, the poor stability of Cu catalysts under high temperatures has restricted their practical applications. The preparation of stable Cu catalysts supported by SiO2 with strong metal–support interaction (SMSI) has thus aroused great interest due to the high abundance,...

Optoelectronic synaptic devices that mimic biological synapses are critical building blocks of artificial neural networks (ANN) based on optoelectronic integration. Here it is shown that an optoelectronic synaptic device based on the hybrid structure of silicon nanocrystals (Si NCs) and poly(3-hexylthiophene) (P3HT) can work with dual modes, exhibi...

The obtained ZJU-28⊃CsPbX 3 crystals exhibit giant two-photon action cross-section and photostability enhancement due to the effects of confinement, passivation and separation derived from ZJU-28 frameworks.

Simultaneously improving the charge transfer and suppressing the charge recombination at the interface is essentially important for high-performance perovskite solar cells (PVSCs). To achieve this goal, in this work, we...

2D PVSCs with “favorable” ion accumulation are realized via thermal–light post-treatment, which increases the built-in potential and device performance.

Switch between second harmonic generation (SHG) and two-photon-pumped (TPP) lasing is scientifically important but hard to be realized. Herein, a host-guest metal-organic framework (MOF) material is prepared, in order to...

Organic-inorganic halide perovskites have exhibited bright prospects in high sensitivity X-ray detection. However, they generally suffer from the severe field-driven polarization issue that remarkably deteriorates the detection performance. Here, we demonstrate that the interfacial electrochemical reaction between Au electrodes and halogen in MAPbI...

SiC crystal is an excellent substrate material for high power electronic devices and high-frequency electronic devices. Being cost-effective and defect-free are the two biggest challenges at present. For the physical vapor transport (PVT) growth of a SiC single crystal, SiC powder is used as the source material, which determines the cost and the qu...

As a common impurity in 4H-silicon carbide (4H-SiC), hydrogen (H) may play a role in the tuning of the electronic properties of 4H-SiC. In this work, we systemically explore the effect of H on the electronic properties of both n -type and p -type 4H-SiC. The passivation of H for intrinsic defects such as carbon vacancies (V C ) and silicon vacancie...

The effects of germanium (Ge)-codoping at 10¹⁸, 10¹⁹ or 10²⁰ cm⁻³ level on the grown-in oxide precipitates in nitrogen (N)-doped Czochralski (NCZ) silicon with the N concentration at 10¹⁴ cm⁻³ level have been investigated. It is found that the Ge-codoping enhances the formation of relatively larger grown-in oxide precipitates. However, such enhance...