High field electron transport properties of bulk ZnO

Abstract

Electron energy loss spectroscopy of ZnO nanocrystals with different oxygen vacancy concentrationsThe Monte Carlo method is used to simulate electron transport for electric field strengths up to 350 kV/cm in bulk, wurtzite structure ZnO. The relevant parts of the conduction bands of a first-principles band structure are approximated by spherically symmetric, nonparabolic valleys located at the ⌫ and U min symmetry points of the Brillouin zone. It is shown that the analytic expressions represent the band structure and the density of states well over a range of nearly 5 eV from the bottom of the conduction band. The simulated electron steady-state drift velocity versus electric field characteristics are calculated for lattice temperatures of 300, 450, and 600 K. For room temperature, drift velocities higher than 3ϫ10 7 cm/s are reached at fields near 250 kV/cm. Examination of the electron energy distributions shows that the strong decrease of the differential mobility with increasing electric field in the field range studied is to be associated with the pronounced nonparabolicity of the central valley and not with transfer of electrons to satellite valleys.

Study of the Piezoelectric Power Generation of ZnO Nanowire Arrays Grown by Different Methods

“…The growth methods [3][4][5] and electrical and mechanical properties of ZnO nanostructures [6][7][8] have been extensively studied and by now they are well known to the research community. [9][10][11] On the other hand, ZnO nanowires have demonstrated sucess in various applications e.g. optoelectronics, [ 12 ] biosensors, [ 13 ] resonators, [ 14 ] electric nanogenerators, [ 15 ] and nanolasers.…”

The dependence of barrier height on temperature for Pd Schottky contacts on ZnO

“…Due to its large exciton binding energy of about 60 meV, which makes it highly efficient in excitonic emission, it has attracted much attention in researchers as it can also be used in ultraviolet and blue-range optoelectronic devices, including lasers [1]. It also has superior electronic parameters such as high breakdown voltage, high electron saturation velocity [2], high thermal conductivity [3] and high radiation tolerance [4], which are better than those of the classical semiconductors, such as Si and GaAs, and is also comparable with the wide band gap semiconductors, like SiC and GaN [5]. Good rectifying ZnO Schottky contacts have been difficult to achieve since the cleaning procedure of the ZnO samples prior to contacts deposition plays a major role.…”

Photoluminescence study of p-type vs. n-type Ag-doped ZnO films

“…For this n-type Ag-doped ZnO sample, the donor sources could be un-activated Ag dopants, 64 Zn interstitials, 14 oxygen vacancies, 65 and other impurities. In this case, the mixed contributions from various ntype charge carriers lead to the complex D 0 X energy trend, i.e., first slightly decrease (10 K-40 K), then increase (40 K-100 K), and finally decrease following the same trends as others (100 K and higher).…”