Peng Wang

Bio: Peng Wang is an academic researcher from University of Maryland, College Park. The author has contributed to research in topics: Thermoelectric cooling & Thermoelectric effect. The author has an hindex of 15, co-authored 32 publications receiving 798 citations.

Optimization of doping concentration for three-dimensional bulk silicon microrefrigerators

Abstract: We designed and fabricated a three-dimensional (3D) silicon microrefrigerator, which demonstrates a cooling power density over 200W/cm with only ~1degC cooling. The high cooling power density is mainly due to the high thermal conductivity and heat spreading effects. These devices have potential application in hot-spots management to reduce the chip peak temperature and realize on chip thermal management. A finite element model is developed to study and optimize these 3D devices. The simulation results showed that the optimized doping concentration to achieve the maximum cooling for these 3D silicon microrefrigerators (5e18 cm-3) is different from the conventional ID device, where S2sigma achieves the maximum at the doping of 5e19 cm-3. At its optimized doping concentration, these silicon microrefrigerators could reach a maximum cooling of 3degC. Further studies prove that this deviation is due to the nonidea factors inherent within the device, e.g. semiconductor-metal contact resistance, Joule-heating from probe contact resistance etc. Thus to optimize the real device, it is necessary to chose a full model considering all the nonideal factors

Simplified Thermal Model of Silicon Thermoelectric Microcooler for On-Chip Hot Spot Remediation

Abstract: Thermal management of on-chip hot spots has become an increasing challenge in recent years because such localized high flux hot spots can not be effectively removed by conventional cooling techniques. The authors have recently explored the novel use of the silicon chip itself as a solid state thermoelectric micrcooler (μTEC) for hot spot thermal management. This paper describes the development and application of a thermo-electric design tool based on closed-form equations for the primary variables. This tool can be used to effectively reduce the complexity and required time for the design and optimization of the silicon microcooler geometry and material properties for on-chip hot spot remediation.Copyright © 2007 by ASME

On-chip cooling by superlattice-based thin-film thermoelectrics

Abstract: There is a significant need for site-specific and on-demand cooling in electronic, optoelectronic and bioanalytical devices, where cooling is currently achieved by the use of bulky and/or over-designed system-level solutions. Thermoelectric devices can address these limitations while also enabling energy-efficient solutions, and significant progress has been made in the development of nanostructured thermoelectric materials with enhanced figures-of-merit. However, fully functional practical thermoelectric coolers have not been made from these nanomaterials due to the enormous difficulties in integrating nanoscale materials into microscale devices and packaged macroscale systems. Here, we show the integration of thermoelectric coolers fabricated from nanostructured Bi2Te3-based thin-film superlattices into state-of-the-art electronic packages. We report cooling of as much as 15 degrees C at the targeted region on a silicon chip with a high ( approximately 1,300 W cm-2) heat flux. This is the first demonstration of viable chip-scale refrigeration technology and has the potential to enable a wide range of currently thermally limited applications.

A comprehensive review of thermoelectric technology: materials, applications, modelling and performance improvement

Abstract: Thermoelectric (TE) technology is regarded as alternative and environmentally friendly technology for harvesting and recovering heat which is directly converted into electrical energy using thermoelectric generators (TEG). Conversely, Peltier coolers and heaters are utilized to convert electrical energy into heat energy for cooling and heating purposes The main challenge lying behind the TE technology is the low efficiency of these devices mainly due to low figure of merit (ZT) of the materials used in making them as well as improper setting of the TE systems. The objective of this work is to carry out a comprehensive review of TE technology encompassing the materials, applications, modelling techniques and performance improvement. The paper has covered a wide range of topics related to TE technology subject area including the output power conditioning techniques. The review reveals some important critical aspects regarding TE device application and performance improvement. It is observed that the intensified research into TE technology has led to an outstanding increase in ZT, rendering the use TE devices in diversified application a reality. Not only does the TE material research and TE device geometrical adjustment contributed to TE device performance improvement, but also the use of advanced TE mathematical models which have facilitated appropriate segmentation TE modules using different materials and design of integrated TE devices. TE devices are observed to have booming applications in cooling, heating, electric power generation as well as hybrid applications. With the generation of electric energy using TEG, not only does the waste heat provide heat source but also other energy sources like solar, geothermal, biomass, infra-red radiation have gained increased utilization in TE based systems. However, the main challenge remains in striking the balance between the conflicting parameters; ZT and power factor, when designing and optimizing advanced TE materials. Hence more research is necessary to overcome this and other challenge so that the performance TE device can be improved further.