Heteroepitaxy and nitrogen doping of high-quality ZnO

Cathodoluminescence of epitaxial GaN and ZnO thin films for scintillator applications

“…The ZnO photon yield shows the two dependencies enumerated above: from the free electron concentration (n), and from whether the additional N 2 O:NO-ZnO buffer layer is grown (up triangles) or not (down triangles). Its growth, leading to a reduction of the density of extended defects such as craters and holes in the surface of ZnO layers deposited atop [28], proves beneficial to radiative BE recombination: a maximum yield of up to 1.370.2 photons/kVe -is obtained with the layer.…”

“…While tertiary-butanol (tBu-OH) was used as group VI-precursor for the growth of an initial 450 nm ZnO buffer layer [25,26], N 2 O was used for the growth of the 0.8-1.6 mm top ZnO layer [27]. In order to obtain nitrogen-compensated ZnO:N top layers, unsymmetrical-dimethylhydrazine (UDMHy) was added to the gas phase [28]. Dimethylzinc was used as group-II precursor.…”

“…For the latter, an upper limit of no5 Â 10 17 cm À3 was determined by ellipsometry. In two samples, an additional 150 nm ZnO buffer was deposited prior to the growth of the top ZnO:N or ZnO:NID layer using a mixture of N 2 O:NO [28].…”

Gallium doping dependence of single-crystal n-type Zno grown by metal organic chemical vapor deposition

“…2 shows room temperature carrier concentrations of Ga-doped ZnO films as a function of Ga/Zn gas mole ratio. C-V method is an alternative characterization technique that has been used extensively on wide bandgap semiconductors such as GaN [17], SiC [18] and ZnO [19,20]. The Hg probe has been used as good Schottky contact even in the case of high carrier concentration up to 10 19 cm À3 [18,19].…”

“…C-V method is an alternative characterization technique that has been used extensively on wide bandgap semiconductors such as GaN [17], SiC [18] and ZnO [19,20]. The Hg probe has been used as good Schottky contact even in the case of high carrier concentration up to 10 19 cm À3 [18,19]. The carrier concentrations (n) can be obtained by n ¼ 2=q ½dðÀ1=C 2 Þ=dV [21], where q is the electron charge, e is the relative dielectric constant with the value of 8.5 for ZnO material, C is the barrier capacitance per unit area, and V is the applied voltage, respectively.…”