ESR studies have been undertaken for various chemical composition of electron beam evapo- rated a-Si_(1-x)Gd_x films with 0<x≤10at%.The experimental results show that the g value changes with (2.0043±0.0001)...ESR studies have been undertaken for various chemical composition of electron beam evapo- rated a-Si_(1-x)Gd_x films with 0<x≤10at%.The experimental results show that the g value changes with (2.0043±0.0001)≤g≤(2.0054±0.0001),the line shape factor l changes with(2.77±0.01)≤l≤(3.10± 0.01)and the linewidth △B_(pp)changes with 6.40×10^(-4)≤△B_(pp)≤7.00×10^(-4)T.The experimental results were analysed with Barnes S.E.dynamic theory of ESR spectrum based on the characteristics of the ESR parameters.It was shown that the changes of ESR parameters depend on the compensation of Gd atoms for the dangling bonds in a-Si film,and the exchange interaction between the conduction electrons and the spins in the host materials.展开更多
The properties of temperature dependence of conductivity σ of electron beam evaporated a-Si_(1-x)Gd_x films which was deposited on some substrates of glass and Al-foil at a substrate temperature of approximately 300...The properties of temperature dependence of conductivity σ of electron beam evaporated a-Si_(1-x)Gd_x films which was deposited on some substrates of glass and Al-foil at a substrate temperature of approximately 300℃ in a background pressure about 2×10^(-4) Pa with a deposition speed about 0.2 nm/s was analyzed and studied.The forms of Gd^(3+) ions in the films,the dangling bond compensation achieved by Gd^(3+) ions and the impurity states compensation achieved by structural disorder aroused by doping Gd ele- ment into a-Si film could be the key factors in resolving the properties of conduction in a-Si_(1-x)Gd_x films.In the temperature region of 290 K<T<500 K,an analysis of conductivity allows to reveal two conductivity regions:(1)conducting conduction of the carriers excited to conductive band,(2)hopping conduction of the carriers in the impurity band near E_F level thermo-excited.展开更多
The key feature of amorphous/crystalline silicon heterojunction solar cells is extremely low surface recombination, which is related to superior passivation on the crystalline silicon wafer surface using thin hydrogen...The key feature of amorphous/crystalline silicon heterojunction solar cells is extremely low surface recombination, which is related to superior passivation on the crystalline silicon wafer surface using thin hydrogenated amorphous silicon （a-Si：H） layers, leading to a high open-circuit voltage. In this work, a two-step method of a-Si：H passivation is introduced, showing excellent interface passivation quality, and the highest effective minority carrier lifetime exceeds 4500μs. By applying a buffer layer deposited through pure silane plasma, the risk of film epitaxial growth and plasma damage caused by hydrogen diluted silane plasma is effectively reduced. Based on this, excellent passivation is realized through the following hydrogen diluted silane plasma process with the application of high density hydrogen. In this process, hydrogen diffuses to a-Si/c-Si interface, saturating residual dangling bonds which are not passivated by the buffer layer. Employing this area of 239 cm2 is prepared, yielding to open-circuit voltage two-step method, a heterojunction solar cell with an up to 735mV and total-area efficiency up to 22.4%.展开更多
文摘ESR studies have been undertaken for various chemical composition of electron beam evapo- rated a-Si_(1-x)Gd_x films with 0<x≤10at%.The experimental results show that the g value changes with (2.0043±0.0001)≤g≤(2.0054±0.0001),the line shape factor l changes with(2.77±0.01)≤l≤(3.10± 0.01)and the linewidth △B_(pp)changes with 6.40×10^(-4)≤△B_(pp)≤7.00×10^(-4)T.The experimental results were analysed with Barnes S.E.dynamic theory of ESR spectrum based on the characteristics of the ESR parameters.It was shown that the changes of ESR parameters depend on the compensation of Gd atoms for the dangling bonds in a-Si film,and the exchange interaction between the conduction electrons and the spins in the host materials.
文摘The properties of temperature dependence of conductivity σ of electron beam evaporated a-Si_(1-x)Gd_x films which was deposited on some substrates of glass and Al-foil at a substrate temperature of approximately 300℃ in a background pressure about 2×10^(-4) Pa with a deposition speed about 0.2 nm/s was analyzed and studied.The forms of Gd^(3+) ions in the films,the dangling bond compensation achieved by Gd^(3+) ions and the impurity states compensation achieved by structural disorder aroused by doping Gd ele- ment into a-Si film could be the key factors in resolving the properties of conduction in a-Si_(1-x)Gd_x films.In the temperature region of 290 K<T<500 K,an analysis of conductivity allows to reveal two conductivity regions:(1)conducting conduction of the carriers excited to conductive band,(2)hopping conduction of the carriers in the impurity band near E_F level thermo-excited.
基金Supported by the National Natural Science Foundation of China under Grant Nos 61574009,11274028,11574014,51302081 and 61575010the Science and Technology Commission of Beijing Municipality under Grant Nos 2151100003315018 and 2151100003515004
文摘The key feature of amorphous/crystalline silicon heterojunction solar cells is extremely low surface recombination, which is related to superior passivation on the crystalline silicon wafer surface using thin hydrogenated amorphous silicon （a-Si：H） layers, leading to a high open-circuit voltage. In this work, a two-step method of a-Si：H passivation is introduced, showing excellent interface passivation quality, and the highest effective minority carrier lifetime exceeds 4500μs. By applying a buffer layer deposited through pure silane plasma, the risk of film epitaxial growth and plasma damage caused by hydrogen diluted silane plasma is effectively reduced. Based on this, excellent passivation is realized through the following hydrogen diluted silane plasma process with the application of high density hydrogen. In this process, hydrogen diffuses to a-Si/c-Si interface, saturating residual dangling bonds which are not passivated by the buffer layer. Employing this area of 239 cm2 is prepared, yielding to open-circuit voltage two-step method, a heterojunction solar cell with an up to 735mV and total-area efficiency up to 22.4%.
