Search

Hanwha Q CELLS now produces its high-efficiency Q.ANTUM solar cell and module technology with p-type Czochralski-grown silicon (Cz-Si) on a multi-GW scale. While maintaining a lean fabrication process, average cell efficiencies exceeding 22 % are achieved in mass production. This results in module powers of more than 330 W by applying wirebased cell interconnection technology to 120 half 6-inch Q.ANTUM cells, narrowing the gap to the highest-efficiency module technologies which use n-type silicon solar cells, at an extremely competitive manufacturing cost. In contrast to conventional passivated emitter and rear cells (PERC), Hanwha Q CELLS’ Q.ANTUM technology is shown to reliably suppress both light-induced degradation (LID) due to boron-oxygen defect formation and Light and elevated Temperature Induced Degradation (LeTID).

A new degradation mechanism (LeTID, Light and elevated Temperature Induced Degradation) for multicrystalline solar cells is presented. The degradation reaches relative power losses of up to 10% on a time scale of several hundreds of hours of carrier injection and at field relevant temperatures. LeTID leads to a highly injection dependent lifetime characteristic after degradation and features a regeneration phase. Characteristics of LeTID as a function of temperature and injection level are presented and a comparison between laboratory and outdoor tests is drawn. LeTID is significantly reduced by adapting the cell process and processing sequence.

In this paper we present the latest results of the high-efficiency Q.ANTUM technology during pilot production at Hanwha Q CELLS. With this dielectric passivated rear cell concept we reach average efficiencies well above 18 % on multicrystalline silicon on continuous running production. The high efficiency cells are converted in an industrial module production with power classes reaching above 270 Wp. We furthermore present field data which show the superior yield performance of modules based on the Q.ANTUM technology during the whole year.

Wavelength-division multiplexing filters are photonic key components for the distribution of multiple optical channels. Microring and racetrack resonators in add/drop configuration can be employed to perform the signal routing. In this work, low-loss hydrogenated amorphous silicon (a-Si:H) was employed as waveguide core material as it is transparent in the near infrared and can be fabricated at low costs and with low temperatures (

In this paper we present the latest R&D results of Q.Cells' high-efficiency solar cell and module concept Q.antum that is currently transferred into mass production. The current work is focused on solar cells and modules produced in our Reiner-Lemoine Research Center. Our optimized rear passivation concept in combination with innovations on the front side of the solar cell resulted in record module efficiencies of 18.5% based on isotropic textured multi-Si substrates. In addition we adopt our Q.antum process on mono-cast (mono-like-multi) Si wafer. These wafers were disposed to an alkaline texturing process and converted into a solar module with record output powers of 283 W. By following the idea of an evolutional cell development a symmetrical passivation that means having the same passivation material on front and rear side could displace cells with different passivation materials on front and rear side. On basis of diffused and non-diffused lifetime test samples we investigate in particular the saturation current density to evaluate the open circuit voltage potential and consequently the feasibility of the evaluated dielectric films for the application as symmetrical passivation scheme. These results were extended by analyzing the implied J-V characteristics to get insights into the feasibility of the investigated passivation schemes.

The standard system architecture of PV installations exposes solar modules to bias voltages of several hundred volts. Recently it became apparent that high bias voltages can have negative effects on the long-term performance of standard screen-printed crystalline silicon solar cells. This paper focuses on the study of this potential induced degradation effect (PID) under laboratory conditions. A corona-discharge assembly was used to polarize mini modules as well as a setup to expose 60-cell modules to high bias under wet conditions. Different encapsulation setups and cell process variations are studied to identify the necessary components leading to PID. I-V measurements, electroluminescence imaging and dark lock-in thermography are employed to obtain detailed characteristics of PID. A correlation between local current loss and shunt conductivity was found. Options to prevent PID on module and cell levels were found and verified experimentally.

In this paper we report on latest results from our pilot production of multi-crystalline (mc) p-type Si cells in the Reiner-Lemoine Research Center at Q-Cells. The cells are double-side contacted and feature a lowly doped emitter, a fineline-printed Ag grid in combination with plating as front metallization and a dielectric passivated rear with local contacts. Using material based on Siemens and upgraded metallurgical grade (100% UMG) feedstock, we achieve stable median cell efficiencies of well above 18 % including the whole brick distribution. Top efficiencies exceeding 19 % (total area) are reached with a standard isotextured front and single anti-reflexion coating. In this work, we show the latest cell optimization progress corresponding to the front metallization process. Furthermore, we report on an independently confirmed cell efficiency of 19.5 % on a large-area multi-crystalline Si solar cell (243 cm2). This efficiency was achieved by implementing next generation process steps. To our knowledge, this result represents the highest energy conversion efficiencies on multi-crystalline Si material achieved so far.

Single wafer identification is a mandatory element of a modern solar cell production [1]. It accelerates the efficiency roadmap of the solar cell and fosters the cost reduction roadmap of the fabrication. The laser marking concept Tra.Q creates an individual code on each and every wafer. This makes process optimization and quality control easier and faster. The solar cells are 100% traceable along the whole value chain [2–4]. Q-Cells has a broad experience of meanwhile 100 million solar cells, being fabricated in the Thalheim manufacturing line. A large statistical database is available. Typically, the code for the individual tracking is engraved onto the bare wafer before the manufacturing process. The big benefits of the single wafer identification are (a) faster learning in production, (b) steeper ramp curves for the introduction of innovations, (c) improved quality control of materials and of products from the suppliers, (d) enhanced transparency to the customer. The single wafer identification helps to make root cause analysis easier and faster and to nail down the key issues in a particular manufacturing site.

To reduce fuel gas consumption, a planar counter-current micro flame ionization detector (μFID) has been developed for mobile applications. In this work, the effect of flame chamber size on the μFID sensitivity is investigated. An FEM model is presented, which predicts sensitivity. The model shows that smaller chambers result in more confined flammable mixtures. Flame observations confirm that smaller chambers generate brighter flames. In addition, sensitivity turns out to be inversely proportional to the distance between the opposing nozzles. Consequently, the smallest flame chamber is most sensitive. At a fourth of the hydrogen consumption (7.5 ml/min), sensitivity is only two times smaller (7.3 mC/gC) than conventionally.

Structured and vertically aligned carbon nanotubes (CNTs) are investigated for their applicability as strain gauges. The CNTs are grown onto an oxidized Si substrate, passivated by a polymer and transferred to a flexible film. This sensor material has a high gauge factor up to 11.5 but also a negative temperature dependence of resistance (TCR with α CNT = −500 ppm/K). For TCR compensation, thin film Pt resistors are added in series on either side of the CNT carpet. Due to the positive TCR of Pt the total TCR can be turned to zero by an appropriate layout of the Pt resistors.

A novel gas sensor has been developed which makes use of the paramagnetic characteristics of oxygen in order to determine its concentration in a sample gas. The aim of this micro paramagnetic oxygen sensor, based on an anisotropic magneto resistance (AMR)-device, is to provide an accurate, reasonably priced and long-term stable solution for stationary and mobile oxygen measurement. The functional principle is to measure an oxygen concentration via its impact on an external magnetic field. The layout of the new micro-electro-mechanical systems (MEMS)-based sensor is kept simple with no moving parts. First measurements of a prototype show a linear response to oxygen concentrations between 0 and 100%.

In this paper we present results from a questionnaire on public displays that aim to increase social cohesion. The displays highlight unexpected social links between passers-by in urban areas, which might lead to the strengthening of existing links and even the creation of new links between people. The results from the questionnaire show that the majority of respondents believes that the proposed displays might increase social cohesion, and about half of them would use them. Some respondents however are afraid for their privacy, security, and being annoyed by strangers. For personal displays, which show information only about single persons, the most popular content are name, interests and contact options. For interpersonal displays, which show information about pairs of people, the most popular information are common friends and common interests. The popularity of the proposed displays however depended strongly on the social context where they would be used. We present a preliminary prototype of a personal display, which is deployed in a university context.

This paper discusses the possibility of total hydrocarbon analysis (THA) with a planar micro flame ionization detector (μFID). Because of reduced fuel gas consumption, the μFID allows for portable applications, which are numerous in the case of THA. Although, the minimum detectable limit (MDL) and fuel gas consumption are still relatively high compared to commercially available portable devices, these first investigations are promising and it is believed that similar or better performance with respect to MDL, linear range and fuel gas consumption can be achieved. Especially, the novel approach of sampling from atmospheric pressure and simultaneously improving flame stability by evacuating the flame chamber is promising.

A rib-like spot-size converter was fabricated with a KOH etched shadow mask. The improvement in coupling and an expansion of the spot-size were evaluated with simulations and confirmed by transmission loss measurements.

A fully integrated mass spectrometer on one chip with a time of flight (TOF) mass filter is presented. This miniaturized mass spectrometer (MMS) is predestinated for mobile measurements, portable applications as well as continuous process monitoring. The MMS uses a microwave plasma electron source providing a high density electron beam for electron impact ionization. The integrated ion optics extracts and focuses the ion beam into the mass separator, where short ion pulses diverge based on their mass-to-charge ratio. The implemented energy filter increases the resolution of the MMS by filtering the ions according to their energy before these are recorded by the detector. MEMS technology allows all critical structures to be fabricated by a one mask anisotropic deep silicon etch. Hence, the MMS is very cost efficient due to its mass producibility. Its small size (5times10 mm) reduces the vacuum requirements by a few orders of magnitude, so that a one stage pumping system achieves the necessary vacuum reducing the overall size of the system. Mass spectra of different gas compositions measured with the MMS are presented.

In the design described a combination of nitride and carbide layers enables the recrystallization of a silicon absorber deposited on graphite or glass substrates. The interface layer siliconcarbide improves the wettability of the silicon film and the substrate during electron beam recrystallization. To prevent entrapment of deep impurities from the glass substrate aluminumnitride is used as a diffusion barrier. Furthermore AlN is used as a supporting mechanical layer during Si crystallization, and titaniumnitride as electrical backside contact. Additionally the absorption of light is enhanced due to reflection at the TiN layer. Efficient Si deposition rates up to 300 nm/min are achieved by means of a PECVD process using trichlorosilane (SiHCl/sub 3/) and hydrogen (H/sub 2/). Scanning of a line shaped electron beam across the silicon surface significantly enlarges the grains as well as it reduces impurities. A crystalline absorber thickness up to 20 /spl mu/m is achieved without epitaxial growth. The layer interfaces are analyzed by scanning electron microscopy, x-ray diffraction and elastic recoil detection analysis.

A new method for the fabrication of a columnar, multicrystalline silicon layer on a graphite substrate is presented. This method basically involves three process steps: (1) deposition of a thin (3-5 /spl mu/m) silicon layer; (2) zone melting recrystallization of this layer with a line electron beam as the heat source to form a multicrystalline seed layer; and (3) thickening of the seed layer by high temperature, epitaxial chemical vapour deposition (CVD) to a thickness of 20-40 /spl mu/m. The recrystallization leads to [110][112]-textured silicon seed layers if sufficiently high scan velocities are applied. The degree of deviation from the ideal [110][112]-texture increases with decreasing scan velocity. The doping level of the seed layer is found to be only weakly affected by the zone melting recrystallization. The epitaxial layer grown on top of the seed layer exhibits a columnar grain structure.

For the first time the Si/C interface in poly-Si photovoltaic thin films on graphite substrate is described. The isostatically pressed graphite is covered with a 3-5 /spl mu/m thick amorphous silicon layer which is recrystallized by the ZMR method (zone melting recrystallization by means of a line electron beam). During ZMR the molten silicon penetrates into the graphite pores, while at the interface /spl beta/-SiC particles with a size of 50-1000 nm were formed (TEM, SEM analysis). Furthermore there exists a "reaction zone" where Si, SiC and C are found by electron diffraction. As a consequence the poly-Si layer shows an excellent adhesion to the substrate. Since there is no continuous electrically insulating SiC layer formed, highly boron doped seed layers show an ohmic contact to the graphite. The investigated poly-Si thin films on graphite substrate offer a great potential for photovoltaic application after epitaxy up to 50 /spl mu/m by LPE or CVD.

This paper describes a high rate deposition process of silicon films by means of plasma-enhanced chemical vapor deposition (PECVD) from trichlorosilane (SiHCl/sub 3/) at low temperatures on graphite substrates. The PECVD-process was investigated for different parameters such as gas composition of SiHCl/sub 3/, H/sub 2/ and Ar, pressure, substrate temperature and RF-power. The deposited films are investigated by energy disperse X-ray analysis to determine the fraction of incorporated chlorine, scanning electron microscopy to characterize the morphology of the film surface, X-ray diffraction to ascertain crystallinity and others. Special interest is paid to the films behavior in a rapid thermal zone melting process to enlarge the grain size for photovoltaic applications.