采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）...采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）硅异质结（SHJ）太阳电池中,研究了硅烷浓度和薄膜厚度对电池性能的影响.实验发现：随着硅烷浓度的降低,本征硅薄膜的晶化率、氢含量、结构因子、光学带隙和光敏性等都在过渡区急剧变化;本征硅薄膜的钝化性能由薄膜的氢含量及氢的成键方式决定.靠近过渡区的薄膜具有较好的致密性和光敏性,氢含量最高,带隙态密度低,且主要以Si H形式成键,对硅片表现出优异的钝化性能,使电池的开路电压大幅提高.但是,当薄膜的厚度过小时,会严重影响其钝化质量.本实验中,沉积本征硅薄膜的最优硅烷浓度为6%（摩尔分数）,且当薄膜厚度为~8 nm时,所制备电池的性能最好.实验最终获得了开路电压为672 m V,短路电流密度为35.1 m A·cm-2,填充因子为0.73,效率为17.3%的nc-Si：H/c-Si SHJ太阳电池.展开更多
We report the reduced-strain gallium-nitride （GaN） epitaxial growth on （0001） oriented sapphire by using quasiporous GaN template. A GaN film in thickness of about 1 μm was initially grown on a （0001） sapphire ...We report the reduced-strain gallium-nitride （GaN） epitaxial growth on （0001） oriented sapphire by using quasiporous GaN template. A GaN film in thickness of about 1 μm was initially grown on a （0001） sapphire substrate by molecular beam epitaxy. Then it was dealt by putting into 45% NaOH solution at 100℃ for lOmin. By this process a quasi-porous GaN film was formed. An epitaxial GaN layer was grown on the porous GaN layer at 1050℃ in the hydride vapour phase epitaxy reactor. The epitaxial layer grown on the porous GaN is found to have no cracks on the surface. That is much improved from many cracks on the surface of the GaN epitaxial layer grown on the sapphire as the same as on GaN buffer directly.展开更多
Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（C...Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.展开更多
We investigate the effect of A/N ratio of the high temperature （HT） AIN buffer layer on polarity selection and electrical quality of GaN films grown by radio frequency molecular beam epitaxy. The results show that l...We investigate the effect of A/N ratio of the high temperature （HT） AIN buffer layer on polarity selection and electrical quality of GaN films grown by radio frequency molecular beam epitaxy. The results show that low Al/N ratio results in N-polarity GaN films and intermediate Al/N ratio leads to mixed-polarity GaN films with poor electrical quality. GaN films tend to grow with Ga polarity on Al-rich AIN buffer layers. GaN films with different polarities are confirmed by in-situ reflection high-energy electron diffraction during the growth process. Wet chemical etching, together with atomic force microscopy, also proves the polarity assignments. The optimum value for room-temperature Hall mobility of the Ga-polarity GaN film is 703cm^2/V.s, which is superior to the N-polarity and mixed-polarity GaN films.展开更多
The effect of high energy electron irradiation on the electrical and optical properties of n-GaN is studied.Hall and photoluminescence measurements are carried out on the samples irradiated with different doses.The re...The effect of high energy electron irradiation on the electrical and optical properties of n-GaN is studied.Hall and photoluminescence measurements are carried out on the samples irradiated with different doses.The results obtained from Hall measurements show that electron concentration and mobility are proportional to electron irradiation doses.The PL results show that the near-band-edge intensity and yellow luminescence intensity decrease continually with the increasing electron irradiation.However,it is found that the ratio of the yellow luminescence intensity to the near-band-edge intensity increases with the increasing of electron irradiation dose.To interpret this phenomenon,we propose two theoretical models based on the charge transport mechanism and rate equations,respectively,and they are in good agreement with the experimental observations.展开更多
文摘采用射频等离子体增强化学气相沉积（RF-PECVD）法在低温、低功率的条件下制备了一系列本征硅薄膜,研究了硅烷浓度（CS）对薄膜微结构、光电特性及表面钝化性能的影响.将本征硅薄膜作为钝化层应用到氢化纳米晶硅/晶硅（nc-Si：H/c-Si）硅异质结（SHJ）太阳电池中,研究了硅烷浓度和薄膜厚度对电池性能的影响.实验发现：随着硅烷浓度的降低,本征硅薄膜的晶化率、氢含量、结构因子、光学带隙和光敏性等都在过渡区急剧变化;本征硅薄膜的钝化性能由薄膜的氢含量及氢的成键方式决定.靠近过渡区的薄膜具有较好的致密性和光敏性,氢含量最高,带隙态密度低,且主要以Si H形式成键,对硅片表现出优异的钝化性能,使电池的开路电压大幅提高.但是,当薄膜的厚度过小时,会严重影响其钝化质量.本实验中,沉积本征硅薄膜的最优硅烷浓度为6%（摩尔分数）,且当薄膜厚度为~8 nm时,所制备电池的性能最好.实验最终获得了开路电压为672 m V,短路电流密度为35.1 m A·cm-2,填充因子为0.73,效率为17.3%的nc-Si：H/c-Si SHJ太阳电池.
文摘We report the reduced-strain gallium-nitride （GaN） epitaxial growth on （0001） oriented sapphire by using quasiporous GaN template. A GaN film in thickness of about 1 μm was initially grown on a （0001） sapphire substrate by molecular beam epitaxy. Then it was dealt by putting into 45% NaOH solution at 100℃ for lOmin. By this process a quasi-porous GaN film was formed. An epitaxial GaN layer was grown on the porous GaN layer at 1050℃ in the hydride vapour phase epitaxy reactor. The epitaxial layer grown on the porous GaN is found to have no cracks on the surface. That is much improved from many cracks on the surface of the GaN epitaxial layer grown on the sapphire as the same as on GaN buffer directly.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.11104148,51101088,and 51171082)the Tianjin Natural Science Foundation,China(Grant Nos.14JCZDJC37700 and 13JCQNJC02800)+1 种基金the Specialized Research Fund for the Doctoral Program of Higher Education,China(Grant No.20110031110034)the Fundamental Research Funds for the Central Universities,China
文摘Cux（Cu2O）1-x（0.09 x 1.00） granular films with thickness about 280 nm have been fabricated by direct current reactive magnetron sputtering. The atomic ratio x can be controlled by the oxygen flow rate during Cux（Cu2O）1-x deposition. Room-temperature ferromagnetism（FM） is found in all of the samples. The saturated magnetization increases at first and then decreases with the decrease of x. The photoluminescence spectra show that the magnetization is closely correlated with the Cu vacancies in the Cux（Cu2O）1-x granular films. Fundamentally, the FM could be understood by the Stoner model based on the charge transfer mechanism. These results may provide solid evidence and physical insights on the origin of FM in the Cu2O-based oxides diluted magnetic semiconductors, especially for systems without intentional magnetic atom doping.
基金Supported the National Natural Science Foundation of China under Grant No 10574130.
文摘We investigate the effect of A/N ratio of the high temperature （HT） AIN buffer layer on polarity selection and electrical quality of GaN films grown by radio frequency molecular beam epitaxy. The results show that low Al/N ratio results in N-polarity GaN films and intermediate Al/N ratio leads to mixed-polarity GaN films with poor electrical quality. GaN films tend to grow with Ga polarity on Al-rich AIN buffer layers. GaN films with different polarities are confirmed by in-situ reflection high-energy electron diffraction during the growth process. Wet chemical etching, together with atomic force microscopy, also proves the polarity assignments. The optimum value for room-temperature Hall mobility of the Ga-polarity GaN film is 703cm^2/V.s, which is superior to the N-polarity and mixed-polarity GaN films.
基金Supported by the Natural Science Foundation of Hebei Province(F2012202083)the Natural Science Foundation of Tianjin(10JCYBJC03000).
文摘The effect of high energy electron irradiation on the electrical and optical properties of n-GaN is studied.Hall and photoluminescence measurements are carried out on the samples irradiated with different doses.The results obtained from Hall measurements show that electron concentration and mobility are proportional to electron irradiation doses.The PL results show that the near-band-edge intensity and yellow luminescence intensity decrease continually with the increasing electron irradiation.However,it is found that the ratio of the yellow luminescence intensity to the near-band-edge intensity increases with the increasing of electron irradiation dose.To interpret this phenomenon,we propose two theoretical models based on the charge transport mechanism and rate equations,respectively,and they are in good agreement with the experimental observations.
