Double-layer emitters with different doping concentrations （DLE） have been designed and prepared for amorphous silicon/crystalline silicon （ct-Si：H/c-Si） hetero- junction solar cells. Compared with the traditiona...Double-layer emitters with different doping concentrations （DLE） have been designed and prepared for amorphous silicon/crystalline silicon （ct-Si：H/c-Si） hetero- junction solar cells. Compared with the traditional single layer emitter, both the experiment and the simulation （AFORS-HET, http：//www.paper.edu.cn/html/releasepaper/2014/04/282/） prove that the double-layer emitter increases the short circuit current of the cells significantly. Based on the quantum efficiency （QE） results and the current-voltage-temperature analysis, the mechanism for the experimental results above has been investigated. The possible reasons for the increased current include the enhancement of the QE in the short wavelength range, the increase of the tunneling probability of the current transport and the decrease of the activation energy of the emitter layers.展开更多
This paper reports that a double N layer （a-Si：H/μc-Si：H） is used to substitute the single microcrystalline silicon n layer （n-μc-Si：H） in n/p tunnel recombination junction between subcells in a-Si：H/μc-Si...This paper reports that a double N layer （a-Si：H/μc-Si：H） is used to substitute the single microcrystalline silicon n layer （n-μc-Si：H） in n/p tunnel recombination junction between subcells in a-Si：H/μc-Si：H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si：H/μc-Si：H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.展开更多
The effect of the parameters on the open-circuit voltage, V_(OC) of a-Si:H/c-Si heterojunction solar cells was explored by an analytical model. The analytical results show that V_(OC) increases linearly with the logar...The effect of the parameters on the open-circuit voltage, V_(OC) of a-Si:H/c-Si heterojunction solar cells was explored by an analytical model. The analytical results show that V_(OC) increases linearly with the logarithm of illumination intensity under usual illumination. There are two critical values of the interface state density(D_(it)) for the open-circuit voltage(V_(OC)), D_(it)^(crit,1) and D_(it)crit,2(a few 1010 cm^(-2)·e V^(-1)). V_(OC) decreases remarkably when D_(it) is higher than D_(it)^(crit,1). To achieve high V_(OC), the interface states should reduce down to a few 1010 cm^(-2)·e V^(-1). Due to the difference between the effective density of states in the conduction and valence band edges of c-Si, the open-circuit voltage of a-Si:H/c-Si heterojunction cells fabricated on n-type c-Si wafers is about 22 mV higher than that fabricated on p-type c-Si wafers at the same case. V_(OC) decreases with decreasing the a-Si:H doping concentration at low doping level since the electric field over the c-Si depletion region is reduced at low doping level. Therefore, the a-Si:H layer should be doped higher than a critical value of 5×10^(18) cm^(-3) to achieve high V_(OC).展开更多
This paper found that the crystalline volume ratio （Xc） of μc-Si deposited on SiNx substrate is higher than that on 7059 glass. At the same silane concentration （SC） （for example, at SC=2%）, the Xc of μc-Si de...This paper found that the crystalline volume ratio （Xc） of μc-Si deposited on SiNx substrate is higher than that on 7059 glass. At the same silane concentration （SC） （for example, at SC=2%）, the Xc of μc-Si deposited on SiNx is more than 64%, but just 44% if deposited on Conning 7059. It considered that the ‘hills＇ on SiNx substrate would promote the crystalline growth of μc-Si thin film, which has been confirmed by atomic force microscope （AFM） observation. Comparing several thin film transistor （TFT） samples whose active-layer were deposited under various SC, this paper found that the appropriate SC for the μc-Si thin film used in TFT as active layer should be more than 2%, and Xc should be around 50%. Additionally, the stability comparison of μc-Si TFT and a-Si TFT is shown in this paper.展开更多
Structural un-uniformity and electrical anisotropy of μc-Si∶H film are investigated in this paper. It is found that the structure of μc-Si∶H film along the direction perpendicular to the substrate is not uniform, ...Structural un-uniformity and electrical anisotropy of μc-Si∶H film are investigated in this paper. It is found that the structure of μc-Si∶H film along the direction perpendicular to the substrate is not uniform, which is modulated by film thickness. In addition, there is a dark conductivity anisotropy along the direction parallel(σ∥) and perpendicular(σ⊥)to the substrate in μc-Si∶H film. The reasons for such an property of μc-Si∶H film and the effect of oxygen contamination are analyzed.展开更多
In order to obtain higher conversion efficiency and to reduce production cost for hydrogenated amorphous silicon/crystalline silicon(a-Si:H/c-Si) based heterojunction solar cells, an a-Si:H/c-Si heterojunction with lo...In order to obtain higher conversion efficiency and to reduce production cost for hydrogenated amorphous silicon/crystalline silicon(a-Si:H/c-Si) based heterojunction solar cells, an a-Si:H/c-Si heterojunction with localized p–n structure(HACL) is designed. A numerical simulation is performed with the ATLAS program. The effect of the a-Si:H layer on the performance of the HIT(heterojunction with intrinsic thin film) solar cell is investigated. The performance improvement mechanism for the HACL cell is explored. The potential performance of the HACL solar cell is compared with those of the HIT and HACD(heterojunction of amorphous silicon and crystalline silicon with diffused junction) solar cells.The simulated results indicate that the a-Si:H layer can bring about much absorption loss. The conversion efficiency and the short-circuit current density of the HACL cell can reach 28.18% and 43.06 m A/cm^2, respectively, and are higher than those of the HIT and HACD solar cells. The great improvement are attributed to(1) decrease of optical absorption loss of a-Si:H and(2) decrease of photocarrier recombination for the HACL cell. The double-side local junction is very suitable for the bifacial solar cells. For an HACL cell with n-type or p-type c-Si base, all n-type or p-type c-Si passivating layers are feasible for convenience of the double-side diffusion process. Moreover, the HACL structure can reduce the consumption of rare materials since the transparent conductive oxide(TCO) can be free in this structure. It is concluded that the HACL solar cell is a promising structure for high efficiency and low cost.展开更多
With in situ optical emission spectroscopy （OES） diagnosis on VHF-generated H2 ＋ SiH4 plasmas,and with the measurements of deposition rate and structure of μc-Si. H thin films fabricated with VHFPECVD technique at...With in situ optical emission spectroscopy （OES） diagnosis on VHF-generated H2 ＋ SiH4 plasmas,and with the measurements of deposition rate and structure of μc-Si. H thin films fabricated with VHFPECVD technique at different substracte temperature, influence of substrate temperature on the deposition of μc-Si.H thin film and on its structural properties have been investigated. The results show that with the increase of substrate temperature,the crystalline volume fraction Xc and average grain size d are enhanced monotonously, but the deposition rate increases firstly and then decreases. The optimized substrate temperature for μc-Si：H thin films deposition under our current growth system is about 210 ℃ ,at which deposition rate O. 8 nm/s of pc-Si;H thin film with Xc-60% and d-9 nm can be obtained.展开更多
基金Acknowledgements This work was supported by the National Natural Science Foundation of China （Grant nos. 61306084, 61464007）, Open Fund of Jiangsu Key Laboratory of Materials and Technology for Energy Conversion （Grant no. NJ20160032）, and Key Research and Development Program of Jiangxi Province, China （Grant no. 2016BBH80043）.
文摘Double-layer emitters with different doping concentrations （DLE） have been designed and prepared for amorphous silicon/crystalline silicon （ct-Si：H/c-Si） hetero- junction solar cells. Compared with the traditional single layer emitter, both the experiment and the simulation （AFORS-HET, http：//www.paper.edu.cn/html/releasepaper/2014/04/282/） prove that the double-layer emitter increases the short circuit current of the cells significantly. Based on the quantum efficiency （QE） results and the current-voltage-temperature analysis, the mechanism for the experimental results above has been investigated. The possible reasons for the increased current include the enhancement of the QE in the short wavelength range, the increase of the tunneling probability of the current transport and the decrease of the activation energy of the emitter layers.
基金Project supported by the State Key Development Program for Basic Research of China (Grant Nos 2006CB202602 and2006CB202603)the National Natural Science Foundation of China (Grant No 60506003)
文摘This paper reports that a double N layer （a-Si：H/μc-Si：H） is used to substitute the single microcrystalline silicon n layer （n-μc-Si：H） in n/p tunnel recombination junction between subcells in a-Si：H/μc-Si：H tandem solar cells. The electrical transport and optical properties of these tunnel recombination junctions are investigated by current voltage measurement and transmission measurement. The new n/p tunnel recombination junction shows a better ohmic contact. In addition, the n/p interface is exposed to the air to examine the effect of oxidation on the tunnel recombination junction performance. The open circuit voltage and FF of a-Si：H/μc-Si：H tandem solar cell are all improved and the current leakage of the subcells can be effectively prevented efficiently when the new n/p junction is implemented as tunnel recombination junction.
基金Project(11374094)supported by the National Natural Science Foundation of ChinaProject(2013HZX23)supported by Natural Science Foundation of Hunan University of Technology,ChinaProject(2015JJ3060)supported by Natural Science Foundation of Hunan Province of China
文摘The effect of the parameters on the open-circuit voltage, V_(OC) of a-Si:H/c-Si heterojunction solar cells was explored by an analytical model. The analytical results show that V_(OC) increases linearly with the logarithm of illumination intensity under usual illumination. There are two critical values of the interface state density(D_(it)) for the open-circuit voltage(V_(OC)), D_(it)^(crit,1) and D_(it)crit,2(a few 1010 cm^(-2)·e V^(-1)). V_(OC) decreases remarkably when D_(it) is higher than D_(it)^(crit,1). To achieve high V_(OC), the interface states should reduce down to a few 1010 cm^(-2)·e V^(-1). Due to the difference between the effective density of states in the conduction and valence band edges of c-Si, the open-circuit voltage of a-Si:H/c-Si heterojunction cells fabricated on n-type c-Si wafers is about 22 mV higher than that fabricated on p-type c-Si wafers at the same case. V_(OC) decreases with decreasing the a-Si:H doping concentration at low doping level since the electric field over the c-Si depletion region is reduced at low doping level. Therefore, the a-Si:H layer should be doped higher than a critical value of 5×10^(18) cm^(-3) to achieve high V_(OC).
基金Project supported by the ‘863＇ Project of National Ministry of Science and Technology （Grant No 2004AA33570）, Key Project of NSFC （Grant No 60437030） and Tianjin Natural Science Foundation （Grant No 05YFJMJC01400）.
文摘This paper found that the crystalline volume ratio （Xc） of μc-Si deposited on SiNx substrate is higher than that on 7059 glass. At the same silane concentration （SC） （for example, at SC=2%）, the Xc of μc-Si deposited on SiNx is more than 64%, but just 44% if deposited on Conning 7059. It considered that the ‘hills＇ on SiNx substrate would promote the crystalline growth of μc-Si thin film, which has been confirmed by atomic force microscope （AFM） observation. Comparing several thin film transistor （TFT） samples whose active-layer were deposited under various SC, this paper found that the appropriate SC for the μc-Si thin film used in TFT as active layer should be more than 2%, and Xc should be around 50%. Additionally, the stability comparison of μc-Si TFT and a-Si TFT is shown in this paper.
文摘Structural un-uniformity and electrical anisotropy of μc-Si∶H film are investigated in this paper. It is found that the structure of μc-Si∶H film along the direction perpendicular to the substrate is not uniform, which is modulated by film thickness. In addition, there is a dark conductivity anisotropy along the direction parallel(σ∥) and perpendicular(σ⊥)to the substrate in μc-Si∶H film. The reasons for such an property of μc-Si∶H film and the effect of oxygen contamination are analyzed.
基金Project supported by the National Key R&D Program of China(Grant No.2018YFB1500403)the National Natural Science Foundation of China(Grant Nos.11964018,61741404,and 61464007)the Natural Science Foundation of Jiangxi Province of China(Grant No.20181BAB202027)
文摘In order to obtain higher conversion efficiency and to reduce production cost for hydrogenated amorphous silicon/crystalline silicon(a-Si:H/c-Si) based heterojunction solar cells, an a-Si:H/c-Si heterojunction with localized p–n structure(HACL) is designed. A numerical simulation is performed with the ATLAS program. The effect of the a-Si:H layer on the performance of the HIT(heterojunction with intrinsic thin film) solar cell is investigated. The performance improvement mechanism for the HACL cell is explored. The potential performance of the HACL solar cell is compared with those of the HIT and HACD(heterojunction of amorphous silicon and crystalline silicon with diffused junction) solar cells.The simulated results indicate that the a-Si:H layer can bring about much absorption loss. The conversion efficiency and the short-circuit current density of the HACL cell can reach 28.18% and 43.06 m A/cm^2, respectively, and are higher than those of the HIT and HACD solar cells. The great improvement are attributed to(1) decrease of optical absorption loss of a-Si:H and(2) decrease of photocarrier recombination for the HACL cell. The double-side local junction is very suitable for the bifacial solar cells. For an HACL cell with n-type or p-type c-Si base, all n-type or p-type c-Si passivating layers are feasible for convenience of the double-side diffusion process. Moreover, the HACL structure can reduce the consumption of rare materials since the transparent conductive oxide(TCO) can be free in this structure. It is concluded that the HACL solar cell is a promising structure for high efficiency and low cost.
文摘With in situ optical emission spectroscopy （OES） diagnosis on VHF-generated H2 ＋ SiH4 plasmas,and with the measurements of deposition rate and structure of μc-Si. H thin films fabricated with VHFPECVD technique at different substracte temperature, influence of substrate temperature on the deposition of μc-Si.H thin film and on its structural properties have been investigated. The results show that with the increase of substrate temperature,the crystalline volume fraction Xc and average grain size d are enhanced monotonously, but the deposition rate increases firstly and then decreases. The optimized substrate temperature for μc-Si：H thin films deposition under our current growth system is about 210 ℃ ,at which deposition rate O. 8 nm/s of pc-Si;H thin film with Xc-60% and d-9 nm can be obtained.
