The /-V-（T） characteristic curves of p-n junctions with the forward voltage as the independent variable, the logarithm of forward current as the dependent variable, and the junction temperature as the parameter, alm...The /-V-（T） characteristic curves of p-n junctions with the forward voltage as the independent variable, the logarithm of forward current as the dependent variable, and the junction temperature as the parameter, almost converge at one point in the first quadrant. The voltage corresponding with the convergence point nearly equals the bandgap of the semiconductor material. This convergence point can be used to obtain the I-V characteristic curve at any temperature.展开更多
A charge density wave(CDW)ground state is observed in polycrystalline Cu_(2)Se below 125 K,which corresponds to an energy gap of 40.9 meV and an electron-phonon coupling constant of 0.6.Due to the polycrystalline stru...A charge density wave(CDW)ground state is observed in polycrystalline Cu_(2)Se below 125 K,which corresponds to an energy gap of 40.9 meV and an electron-phonon coupling constant of 0.6.Due to the polycrystalline structure,the Peierls transition process has been expanded to a wide temperature range from 90 K to 160 K.The Hall carrier concentration shows a continuous decrease from 2.1×10^(20)to 1.6×10^(20)cm^(-3)in the temperature range from 160 K to 90 K,while almost unchanged above 160 K and below 90 K.After entering the CDW ground state,a wave-like fluctuation was observed in theI-Vcurve near 50 K,which exhibits a periodic negative differential resistivity in an applied electric field due to the current.We also investigated the doping effect of Zn,Ni,and Te on the CDWground state.Both Zn and Ni doped Cu_(2)Se show a CDW character with increased energy gap and electron-phonon coupling constant,but no notable Peierls transition was observed in Te doped Cu_(2)Se.Similar wave-likeI-Vcurve was also seen in Cu_(1.98)Zn_(0.02)Se near 40 K.The regular fluctuation in the dcI-Vcurve was not magnetic field sensitive,but temperature and sample size sensitive.展开更多
文摘The /-V-（T） characteristic curves of p-n junctions with the forward voltage as the independent variable, the logarithm of forward current as the dependent variable, and the junction temperature as the parameter, almost converge at one point in the first quadrant. The voltage corresponding with the convergence point nearly equals the bandgap of the semiconductor material. This convergence point can be used to obtain the I-V characteristic curve at any temperature.
基金This work is supported by“Solid State Solar-Thermal Energy Conversion Center(S3TEC)”an Energy Frontier Research Center funded by the U.S.Department of Energy,Office of Science,Office of Basic Energy Science under award number DE-SC0001299/DEFG02-09ER46577(Z.F.R.).C.O.wishes to thank Robert D.Farrell,S.J.for editing the MS and the Trustees of Boston College for their financial support.
文摘A charge density wave(CDW)ground state is observed in polycrystalline Cu_(2)Se below 125 K,which corresponds to an energy gap of 40.9 meV and an electron-phonon coupling constant of 0.6.Due to the polycrystalline structure,the Peierls transition process has been expanded to a wide temperature range from 90 K to 160 K.The Hall carrier concentration shows a continuous decrease from 2.1×10^(20)to 1.6×10^(20)cm^(-3)in the temperature range from 160 K to 90 K,while almost unchanged above 160 K and below 90 K.After entering the CDW ground state,a wave-like fluctuation was observed in theI-Vcurve near 50 K,which exhibits a periodic negative differential resistivity in an applied electric field due to the current.We also investigated the doping effect of Zn,Ni,and Te on the CDWground state.Both Zn and Ni doped Cu_(2)Se show a CDW character with increased energy gap and electron-phonon coupling constant,but no notable Peierls transition was observed in Te doped Cu_(2)Se.Similar wave-likeI-Vcurve was also seen in Cu_(1.98)Zn_(0.02)Se near 40 K.The regular fluctuation in the dcI-Vcurve was not magnetic field sensitive,but temperature and sample size sensitive.
