Deposits of clastic carbonate-dominated (calciclastic) sedimentary slope systems in the rock record have been identified mostly as linearly-consistent carbonate apron deposits, even though most ancient clastic carbonate slope deposits fit the submarine fan systems better. Calciclastic submarine fans are consequently rarely described and are poorly understood. Subsequently, very little is known especially in mud-dominated calciclastic submarine fan systems. Presented in this study are a sedimentological core and petrographic characterisation of samples from eleven boreholes from the Lower Carboniferous of Bowland Basin (Northwest England) that reveals a >250 m thick calciturbidite complex deposited in a calciclastic submarine fan setting. Seven facies are recognised from core and thin section characterisation and are grouped into three carbonate turbidite sequences. They include: 1) Calciturbidites, comprising mostly of highto low-density, wavy-laminated bioclast-rich facies; 2) low-density densite mudstones which are characterised by planar laminated and unlaminated muddominated facies; and 3) Calcidebrites which are muddy or hyper-concentrated debrisflow deposits occurring as poorly-sorted, chaotic, mud-supported floatstones. These

Phd by thesis

Silicon nanowire arrays (SiNWs) on a planar silicon wafer can be fabricated by a simple metal-assisted wet chemical etching method. They can offer an excellent light harvesting capability through light scattering and trapping. In this work, we demonstrated that the organic–inorganic solar cell based on hybrid composites of conjugated molecules and SiNWs on a planar substrate yielded an excellent power conversion efficiency (PCE) of 9.70%. The high efficiency was ascribed to two aspects: one was the improvement of the light absorption by SiNWs structure on the planar components; the other was the enhancement of charge extraction efficiency, resulting from the novel top contact by forming a thin organic layer shell around the individual silicon nanowire. On the contrary, the sole planar junction solar cell only exhibited a PCE of 6.01%, due to the lower light trapping capability and the less hole extraction efficiency. It indicated that both the SiNWs structure and the thin organic layer top contact were cr...

Hybrid heterojunction solar cell based on organic-inorganic silicon nanowire array architecture.

Foreword.- Introduction.- Status of heterojunction solar cell R&D.- Basic features of Heterojunctions illustrated by selected experimental methods and results.- Deposition methods of thin film silicon.- Electronic properties of ultrathin a-Si:H layers and the a-Si:H/c-Si interface.- Degradation of (bulk and thin film) a-Si and interface passivation.- Photoluminescence and electroluminescence for a Si:H/c Si device and interface characterization.- Deposition and properties of transparent conductive oxides.- Metallization and formation of contacts.- Electrical and optical characterization of a-Si:H/c Si cells.- Wet-chemical pre-treatment of c Si for a-Si:H/c-Si heterojunctions.- Theory of heterojunctions and the determination of band offsets from electrical measurements.- Modeling and simulation of a Si:H/c Si cells.- Surface passivation using ALD Al2O3.- Introduction to AFORS-HET.- Hands-on experience with simulation tools.- a-Si:H/c-Si heterojunction and other high efficiency solar cells: a comparison.- Rear contact cells.- Progress in systematic industrialization of Hetero-Junction-based Solar Cell technology.

Physics and Technology of Amorphous-Crystalline Heterostructure Silicon Solar Cells

This work analyzes heterojunction with intrinsic thin layer (HIT) solar cells using numerical simulations. The differences between the device physics of cells with p- and n-type crystalline silicon (c-Si) wafers are substantial. HIT solar cells with n-type wafers essentially form a n/p/n structure, where tunneling across the junction heterointerfaces is a critical transport mechanism required to attain performance exceeding 20%. For HIT cells with p-type wafers, only tunneling at the back-contact barrier may be important. For p-wafer cells, the hydrogenated amorphous silicon (a-Si:H) between the indium tin oxide (ITO) and crystalline silicon may act as a passivating buffer layer but, otherwise, does not significantly contribute to device performance. For n-wafer cells, the carrier concentration and band alignment of this a-Si:H layer are critical to device performance.

The role of amorphous silicon and tunneling in heterojunction with intrinsic thin layer (HIT) solar cells

Advances in a-Si:H/c-Si heterojunction solar cell fabrication and characterization

Physical aspects of a-Si:H/c-Si hetero-junction solar cells

We report on the basic properties of a-Si:H/c-Si hetero-junctions, their effects on the recombination of excess carriers and its influence on the a-Si:H/c-Si hetero-junction solar cells. For this purpose we measured the gap state density distribution in thin a-Si:H layers, determined its dependence on deposition temperature and doping by an improved version of near UV-photoelectron emission spectroscopy. Furthermore, the Fermi level position in the a-Si:H and the valence band offset were directly measured. In combination with interface specific methods such as surface photovoltage analysis and our numerical simulation program AFORS-HET, we are able to find out the optimum in wafer pretreatment, doping and deposition temperature for efficient a-Si:H/c-Si solar cells without an i-type a-Si:H buffer layer. By a deposition at 210degC with an emitter doping of 2000 ppm of B2 H6 on a well cleaned pyramidal structured c-Si(p) wafer we reached 19.8 % certified efficiency

Physical and Technological Aspects of a-Si:H/c-Si Hetero-Junction Solar Cells

We report on the optimization of hydrogenated amorphous silicon/crystalline silicon (a-Si:H/c-Si) heterojunction solar cells which were completely processed at temperatures below 230°C. Efficient solar cells based on both n-type and on p-type c-Si substrates were performed. In contrast to the approach from Sanyo [1] no additional a-Si:H(i) buffer layer was used. Instead the conditions of the amorphous silicon preparation by conventional plasma enhanced chemical vapor deposition (PECVD) were optimized and several wet- or plasma chemical treatments were applied to improve the interface properties. The highest efficiencies so far are 17.4% on p-type c-Si wafers and 19.8% on n-type c-Si wafers.

Ch. Schubert

Papers

Physical aspects of a-Si:H/c-Si hetero-junction solar cells

Physical and Technological Aspects of a-Si:H/c-Si Hetero-Junction Solar Cells

Optimization of Interface Properties in a-Si:H/c-Si Heterojunction Solar Cells