2011.4
About Instruments Today No. 181
CIGS Thin Film Solar Cells
CIGS Solar Cell — The Development of Cd-Free Buffer Layer Materials and Process Technology [ 下載 PDF ]
Chih-Pin Tsai, Chih-Yu Chien, Shin-Yuan We, Chih-Huang Lai
The development of Cd-free buffer layer is one of the most important topics for the evolution of CIGS solar cell. Nowadays, the CdS is typically used as buffer layer in high efficiency CIGS solar cell. However, Cd is very toxic and makes great impact to our environment. To reduce the usage of Cd and keep the high efficiency of CIGS solar cell for the commercializing demand, a lot of effort has been done for the exploration of Cd-free buffer layer. In this article, we introduced the main functions of buffer layer in CIGS solar cell and the technological challenges on buffer layer deposition for mass production. Three potential candidate ZnS, In2S3 and Zn1−xMgxO to replace the CdS buffer layer and their corresponding deposition technologies such as sputter, evaporation and ALD were discussed.
High Efficiency CIGS Solar Cell Developed by Coevaporation and Sputtering/Selenization Methods [ 下載 PDF ]
Jia-Min Shieh, Bau-Tong Dai, Chang-Hong Shen, Yu-Jen Hsiao, Ting-Jen Hsueh, Tsung-Ta Wu
Copper indium gallium selenide (CIGS) thin film solar cells attracted a lot of attention due to the low-cost, light weight, flexible, long life and other features and advantages. National Nano Laboratory (NDL) possess G1 size (30 × 40 cm2) continues sputtering system and high precise co-evaporation deposition system that can deposit high-quality p-type CIGS thin film on glass. NDL has established the manufacturing technology of CIGS solar cells, included high-efficiency Cd-free CIGS solar cell with conversion efficiency of 14% and CIGS flexible solar cell with conversion efficiency of 6% both by co-evaporation method, and non-toxic CIGS solar cell with mass production possibility with conversion efficiency of 6.4% by sputtering/selenization methods.
"The Measurements of the Electro-Optical Characterization for Cu(In,Ga)Se2 Thin-Film Solar Cells" [ 下載 PDF ]
Wen-Chieh Shih, Yan-Huei Wu
Solar cell is the photovoltaic device which can generate electrical power by absorbing sunlight. The analysis of electro-optical characterization is the key issue related to the performance of solar cells. In this article, we will introduce the electrical and optical measurements of Cu(In,Ga)Se2 thin film solar cells. At first, we demonstrate three capacitance-voltage (C-V) techniques, including general C-V method, admittance spectroscopy, drive-level capacitance profiling. The conductive secondary phase in CIGS film will be discussed. The optical measurements are photoluminescence spectrum and time-resolved photoluminescence which can be analyzed for the quality and the composition of thin-film. These two optical techniques can provide the harmless and untouchable in-line measurement for the fabrication.
Copper Indium Gallium Diselenide Thin Film Solar Cells [ 下載 PDF ]
Tian-Jue Hong, Chih-Huang Lai
Copper indium gallium diselenide (CIGS) is one of most promising materials for thin film solar cells. Copper indium gallium diselenide solar cells have shown stable, high conversion efficiencies thin film solar cells, exceeded 20%. Present article discusses the concept of solar cell operation principle, and several preparation methods for copper indium gallium diselenide thin film solar cells.
The Three-Dimensional Depolarization Neutron Beamline at Tsing Hua Open Pool Reactor for the Measurement of Magnetic Domain of a Bulk Material [ 下載 PDF ]
Chih-Hao Lee, Lieh-Jeng Chang
We introduce a technique of neutron depolarization measurement to observe interior magnetic domains of magnetic materials. An apparatus of three-dimensional depolarized neutron beam has been setup at W-3 beamport of Tsing Hua Open Pool Reactor. When polarized neutrons pass through a magnetic material, the existence of magnetic domains will alter the direction and magnitude of the polarized neutron vector. This alternation would provide useful information of the average domain size, the averaged strength of the induced field, and the mean square directional cosine of the material.
Fabrication of Optical Fiber Sensor by the Femtosecond Laser Precision Manufacturing System [ 下載 PDF ]
Chien-Hsing Chen, Wei-Te Wu, Jaw-Luen Tang, Lai-Kwan Chau
Femtosecond laser manufacturing of fiber optic sensor has advantages as compared to conventional laser process such as high precision, fast fabrication, and without creating laser-induced heat affected zone. This report will introduce the principles of several optical fiber sensors and the technology developed by our laboratory to fabricate D-shaped window on optical fiber sensor by femtosecond laser manufacturing.
Surface Profile Measurement with Instantaneous Phase-Shifting Interferometry [ 下載 PDF ]
Yi-liang Du, Terry Yuan-Fang Chen
Surface profile measurement is an important technique in the semiconductor industry and the manufacturing of the optical components. Due to its noncontact nature, full-field, high accuracy and resolution, phase-shifting interferometry (PSI) has been quite evolved in surface profile measurement of high-tech products. However, movement of the phase shifter, the vibration and air disturbance, and longer image-grabbing time make the PSI measurement inaccurate, and not suitable for on-line measurement. In this context, a measurement system that is capable to grab the phase-shifted interferometric images instantaneously (or simultaneously) for surface profile measurement is introduced. Using the polarization phase-shifting interferometry principles and through a four-image combining device, the system allows the four phase-shifted images to be grabbed by one CCD simultaneously. Then the grey-level values of the four images can be adjusted, digitally aligned to calculate the phase. The surface profile is obtained after phase unwrapping. Test of the system on a flat mirror and a silicon wafer demonstrates its usefulness. The accuracy and stability of the measurement is discussed. The development of such system will reduce the effect due to environmental vibration, and thus applicable for practical use.
Mechanical Characteristics of AlGaN Thin Films by Nanoindentation and Transmission Electron Microscopy [ 下載 PDF ]
Sheng-Rui Jian, Ting-Chun Lin, Ping-Feng Yang, Yi-Shao Lai, Jenh-Yih Juang
This article reports a nanomechanical response study of the contact-induced deformation behavior in Al0.16Ga0.84N thin film by means of a combination of nanoindentation and the cross-sectional transmission electron microscopy (XTEM) techniques. Al0.16Ga0.84N thin film is deposited by using the metal-organic chemical vapor deposition (MOCVD) method. Hardness and Young's modulus of the Al0.16Ga0.84N films were measured by a Berkovich nanoindenter operated with the continuous contact stiffness measurements (CSM) mode. The obtained values of the hardness and Young's modulus are 19.76 ± 0.15 GPa and 310.63 ± 9.41 GPa, respectively. The XTEM images taken in the vicinity regions just underneath the indenter tip revealed that the multiple 'pop-ins' observed in the load-displacement curve during loading are due primarily to the activities of dislocation nucleation and propagation. The absence of discontinuities are in the unloading segments of load-displacement curve suggests that no pressureinduced phase transition was involved.
A Study of the Measurement of the Deformation of a High-Speed Rotational Mirror [ 下載 PDF ]
Po-Hsuan Huang, Ting-Ming Huang
A high-speed rotational mirror can serve as a modulation mechanism in the optoelectric experiments. Dynamic stability shall be checked before applying this mirror to avoid destroying the rotational spindle. During the highspeed rotation, the mirror may suffer from deformation such that the signal of the experiments will be unstable. The authors propose a measurement method to study the deformation of the mirror at a rotational speed ranging from 5000 to 30000 rpm. The experiment and the numerical simulation show that the mirror deforms. Two kinds of measurement types are presented, and the same results can be obtained.
LED Direction Indicators Design with Asymmetric Fresnel Lens [ 下載 PDF ]
Yuan Chang Liou, Shin-Kuan Chen, Pen-Hsiag Lin
The paper presents the LED direction indicators design with asymmetric Fresnel lens, which meets the ECE R6 criterion. The opto-mechanical design software, ASAP, is adopted for the analysis of light flux. The results show that Lambertian LED and the asymmetric Fresnel lens can produce an asymmetric lightspot which is about 20 degree in horizontal and 10 degree in vertical. Therefore, the minimum requirement of LED light flux is 38–55 lm lower in the design; it is lower than that for thin flat-convex lens, and much lower than the traditional bulb P21W.
