D. Braunger, Th. Durr, D. Hariskos, C. Koble, T. Walter, N. Wieser, H. Schock
{"title":"Improved open circuit voltage in CuInS/sub 2/-based solar cells","authors":"D. Braunger, Th. Durr, D. Hariskos, C. Koble, T. Walter, N. Wieser, H. Schock","doi":"10.1109/PVSC.1996.564300","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564300","url":null,"abstract":"The conversion efficiency of thin film solar cells based on CuInS/sub 2/ (/spl eta/=12%) is mainly limited by a moderate open circuit voltage (/spl ap/720 mV). This limitation can be overcome by modifying the absorber/buffer interface leading to open circuit voltages exceeding 800 mV. The addition of ZnS to the CuInS/sub 2/ as well as adjusting the preparation conditions for the CdS-buffer leads to an increased V/sub oc/. The coevaporation of ZnS or CdS additives and diffusion from precursor layers for two types of fabrication processes has been examined: codeposition of the elements and diffusion of Cu and S into In/sub x/S/sub y/ layers. The addition of ZnS leads to Zn-rich segregations on the CuInS/sub 2/ surface. No shift of the bandgap due to the Zn incorporation could be measured. Additionally, an improved sulfur incorporation using the binary In/sub 2/S/sub 3/ as the In and S source was found.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"109 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117209227","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"An experimental and computer simulation study of the role of CdS in CIS-type solar cells","authors":"J. Hou, S. Fonash, J. Kessler","doi":"10.1109/PVSC.1996.564289","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564289","url":null,"abstract":"An experimental and computer simulation study of the \"red kink\" current-voltage features seen in many CdS/Cu(In,Ga)Se/sub 2/ solar cells has been undertaken to gain more insight into cell operation and to address the controversy over the role of the CdS layer. The study shows that in structures with chemical bath deposited CdS: (1) the \"red kink\" effect is due to a low free electron concentration and high trap state concentration in the CdS layer, (2) the direct cause of the \"red kink\" is current modulated free electron concentration in the CdS, and (3) under white light the positive space charge built-up in CdS traps greatly enhances the photo-carrier collecting electric field in the absorber layer. Therefore, the CdS layer has an important role in the junction under white light.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"14 7","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120822318","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Validated simulation for thermal regulation of photovoltaic wall structures","authors":"Hongxing Yang, R. H. Marshall, B. Brinkworth","doi":"10.1109/PVSC.1996.564409","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564409","url":null,"abstract":"A simulation model for PV wall structures is developed so that its thermal and electrical behaviour can be analysed and predicted. The air flow in the air duct behind the PV modules, and the heat transfer through the backing structure can also be calculated. The numerical solution of the governing equations for the air flow in the air duct yield the air velocity and temperature distributions along the air duct. An air duct with lower height and deeper depth can achieve a better performance of ventilation effect for PV modules. An indoor PV wall test rig was built for validation of the simulation model. With a well designed ventilated PV wall structure, the PV cell temperature can be reduced by 15/spl deg/C and the PV module power output can be increased by 8.0% compared with nonventilation PV wall structures. The simulation model predicts well the air flow behaviour inside the air duct.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"26 2","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"120851830","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
L. Fraas, H. Xiang, J. Samaras, R. Ballantyne, D. Williams, S. Hui, L. Ferguson
{"title":"Hydrocarbon fired thermophotovoltaic generator prototypes using low bandgap gallium antimonide cells","authors":"L. Fraas, H. Xiang, J. Samaras, R. Ballantyne, D. Williams, S. Hui, L. Ferguson","doi":"10.1109/PVSC.1996.563963","DOIUrl":"https://doi.org/10.1109/PVSC.1996.563963","url":null,"abstract":"Low bandgap gallium antimonide photovoltaic cells make hydrocarbon-fired thermophotovoltaic generators practical. Here, the authors describe four prototype generators. In the smallest unit, a candle flame is surrounded with a bracelet of 16 GaSb cells, producing enough power to operate a transistor radio. In the second unit, they insert an IR emitter coil in a Bunsen burner flame and surround it with 20 GaSb cells. This produces over 2 W, enough to operate a \"boom box\" radio/tape player. A third unit is a wall-mounted combination room heater and battery charger for off-grid remote applications. This cogeneration unit produces 30 W of electricity and 10,000 BTU per hour of heat. The fourth unit is a more efficient cylindrical generator complete with exhaust heat regeneration. This unit generates 130 W; larger versions could eventually replace home furnaces and supply heat and electricity for homes in the next Century.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121018523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
M. Flórez, W. De La Cruz, P. Teherán, L. Cota, G. Gordillo
{"title":"Low resistance contact to CdTe thin films","authors":"M. Flórez, W. De La Cruz, P. Teherán, L. Cota, G. Gordillo","doi":"10.1109/PVSC.1996.564283","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564283","url":null,"abstract":"A new procedure to realize low resistance contact to polycrystalline CdTe thin films for solar cells deposited by CSS method is presented. Initially, the CdTe samples are etched with an oxidant agent in order to form a Te-rich surface layer; subsequently the CdTe samples are dipped in a CuCl solution to form a p/sup +/-Cu/sub x/Te (1/spl les/x/spl les/2) layer through an ion-exchange chemical reaction; finally, the samples were contacted with Cu and Cu/Au deposited by thermal evaporation and C:Cu deposited by DC magnetron sputtering. Contact resistivities of 0.16 /spl Omega/cm/sup 2/ were obtained using sulphochromic solution as oxidant agent and Cu as electrical contact. The changes induced in the CdTe-surface by the different surface treatments were studied by means of XRD and AES measurements.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"81 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"121056149","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Highly textured ZnO thin films and SnO/sub 2//ZnO bilayer films prepared by the pyrosol process","authors":"Jinsoo Song, C. Lee, K. Lim, K. Yoon, K. Yu","doi":"10.1109/PVSC.1996.564333","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564333","url":null,"abstract":"Indium-doped ZnO(ZnO:In) films have been prepared on heated Corning 7059 glass by pyrosol spray method. Indium improves the conductivity as an n-type dopant and stimulates grain growth. For films grown at 400/spl deg/C, resistivity of ZnO films decreased from 1.3/spl times/10/sup -2/ /spl Omega/ cm to 3.5/spl times/10/sup -3/ /spl Omega/ cm by doping 1 wt% indium. Furthermore, ZnO:In films grown at higher temperture revealed larger grain sizes and a higher texturization compared to undoped films. A highly textured ZnO:In films with resistivity of 2.5/spl times/10/sup -3/ /spl Omega/ cm, total transmittance of 80% was made at the substrate temperature of 475/spl deg/C, and was milky looking. ZnO:In films did not degrade under hydrogen plasma, and was applied as a protection barrier against hydrogen plasma and the light scattering layer in the SnO/sub 2//ZnO bilayer films. Bilayer films have a resistivity of 8.8/spl times/10/sup -4/ /spl Omega/ cm and total transmittance of 84% at 550 nm, and was proved to have an excellent hydrogen plasma durability.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"2424 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"127476546","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Stress testing of CdTe solar cells","authors":"P. Meyers, J. Phillips","doi":"10.1109/PVSC.1996.564246","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564246","url":null,"abstract":"CdTe/CdS solar cells have been known to exhibit various combinations of reversible and irreversible degradation of conversion efficiency after being subjected to temperature, voltage and illumination at levels which equal or surpass those expected in field conditions. This paper describes a series of measurements designed to quantify these phenomena. The QE and light and dark J-V characteristics of a set of CdTe devices were measured, then devices were subjected to various combinations of stresses within the parameter space of 0-70 mW/cm/sup 2/ illumination, -0.5 V to +5 mA/cm/sup 2/ electrical bias, and temperatures from 72/spl deg/ to 112/spl deg/C. The device characteristics were measured and changes are interpreted in the context of an equivalent circuit which includes the effects of both the main junction diode, series resistor and a rectifying back contact.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"48 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"124937072","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Z. Shellenbarger, M. Mauk, L. C. Dinetta, G. Charache
{"title":"Recent progress in InGaAsSb/GaSb TPV devices","authors":"Z. Shellenbarger, M. Mauk, L. C. Dinetta, G. Charache","doi":"10.1109/PVSC.1996.563951","DOIUrl":"https://doi.org/10.1109/PVSC.1996.563951","url":null,"abstract":"AstroPower is developing InGaAsSb thermophotovoltaic (TPV) devices. This photovoltaic cell is a two-layer epitaxial InGaAsSb structure formed by liquid-phase epitaxy on a GaSb substrate. The (direct) bandgap of the In/sub 1-x/Ga/sub x/As/sub 1-y/Sb/sub y/ alloy is 0.50 to 0.55 eV, depending on its exact alloy composition (x,y), and is closely lattice-matched to the GaSb substrate. Internal quantum efficiencies as high as 95% have been measured at a wavelength of 2 microns. At a wavelength of 1 micron, internal quantum efficiencies of 55% have been observed. At a current density of 1.6 A/cm/sup 2/, an open-circuit voltage of 0.250 V and a fill factor of 60% have been measured. Our results to date show that the GaSb-based quaternary compounds provide a viable and high performance energy conversion solution for thermophotovoltaic systems operating with 1000 to 1500/spl deg/C source temperatures.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"23 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116188009","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Operation and component testing of a solar thermophotovoltaic power system","authors":"K. Stone, N. Fatemi, L. Garverick","doi":"10.1109/PVSC.1996.564401","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564401","url":null,"abstract":"Components of a solar thermophotovoltaic (STPV) power system have been developed and tested. This paper describes the principle of operation of a STPV system, the conceptual design of the TPV conversion unit, and some of the operating features which make it attractive for both space and terrestrial application. McDonnell Douglas Aerospace (MDA) conducted over 600 hrs. Of on-sun tests and reached temperatures above 1573 K during these tests. Essential Research has developed and tested selective emitter and blackbody-based TPV converters with efficiencies approaching 30%. Analytical models developed by MDA and Essential Research were validated by test data and used to develop a conceptual design and to estimate the system performance. These models indicate the efficiency of a STPV power conversion system to be greater than 20% using current state-of-the-art technology and could increase to above 35% using advance technology.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"326 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"116542816","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
F. Abulfotuh, T. Wangensteen, R. Ahrenkiel, L. Kazmerski
{"title":"Optical properties and defect levels in a surface layer found on CuInSe/sub 2/ thin films [solar cells]","authors":"F. Abulfotuh, T. Wangensteen, R. Ahrenkiel, L. Kazmerski","doi":"10.1109/PVSC.1996.564297","DOIUrl":"https://doi.org/10.1109/PVSC.1996.564297","url":null,"abstract":"In this paper, the authors have used photoluminescence (PL) and wavelength scanning ellipsometry (WSE) to clarify the relationship among the electro-optical properties of copper indium diselenide (CIS) thin film solar cells, the type and origin of dominant defect states, and device performance. The PL study has revealed several shallow acceptor and donor levels dominating the semiconductor. PL emission from points at different depths from the surface of the CIS sample has been obtained by changing the angle of incidence of the excitation laser beam. The resulting data were used to determine the dominant defect states as a function of composition gradient at the surface of the chalcopyrite compound. The significance of this type of measurement is that it allowed the detection of a very thin layer with a larger bandgap (1.15-1.26 eV) than the CIS present on the surface of the CIS thin films. The presence of this layer has been correlated by several groups to improvement of the CIS solar cell performance. An important need that results from detecting this layer on the surface of the CIS semiconductor is the determination of its thickness and optical constants (n, k) as a function of wavelength. The thickness of this surface layer is about 500 /spl Aring/.","PeriodicalId":410394,"journal":{"name":"Conference Record of the Twenty Fifth IEEE Photovoltaic Specialists Conference - 1996","volume":"15 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"1996-05-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"122543523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}