Schottky contacts to hydrogen doped ZnO

Abstract

High resistivity (≥1 kΩ cm) hydrothermally grown single crystal ZnO wafers were modified by hydrogen implantation. The implantation has been performed with multiple energies in order to form a box‐like profile with a depth of 4 μm and two different concentrations of 8 × 1017 H/cm3 and 1.5 × 1018 H/ cm3. A subsequent annealing at 200 °C for 30 min in N2 resulted in the formation of a highly conductive layer. Pd con‐ tacts deposited on the implanted side showed rectifying behaviour by up to three orders of magnitude. However by capacitance vs. voltage (C –V) technique a carrier concentration significantly lower than the one expected according to the implanted H content was measured suggesting the presence of a high density of compensating centers and/or an incomplete activation of H as a donor. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)

Schottky contacts on differently grown n-type ZnO single crystals

“…2,6 This phenomenon was correlated with the presence of interface states or the influence of deep recombination centers. The plot of ln͓͑I − ͑V − IR S ͒ / R Sh ͔ / ͕1 − exp͓−e͑V − IR S ͒ / kT͔͖͒ as a function of the bias V applied to the diode gives directly the ideality factor n of Schottky diode.…”

Role of intrinsic and extrinsic defects in H implanted hydrothermally grown ZnO

“…62 Finally 22 On the other hand, as mentioned above, as H or 2 H implanted samples are highly resistive and a subsequent annealing at 200 C has been found to be necessary for obtaining layers with optimal electrical characteristics. 9,11,27 Then, the presented calculations suggest oxygen sublattice related defects as a source of compensating centers responsible for the observed postimplantation resistivity increase. Indeed, the reported theoretically calculated temperature for annealing out of primary defects situated in the oxygen sublattice by O 2À i migration is 170 C, which is consistent with the annealing temperature experimentally found as well as the defect nature deduced here.…”

“…Postimplantation annealing at 200 C has been found necessary to obtain layers with optimal electrical characteristics in previous works. 9,11,27 Therefore, 30 min long annealing in N 2 flow at 200 C was performed on all samples. An additional anneal of 30 min in air at 200 C for samples A, B, C, and D was carried out in order to 0 , C 0 , respectively.…”

Synthesis of ZnO and transition metals doped ZnO nanostructures, their characterization and sensing applications

“…In addition, the performance of the sensors can be improve by doping ZnO nanostructure with different metals or by alloyed ZnO with other metal oxides. This is due to the dopant influenced on the properties ZnO nanostructures such as the band gap, optical property and electrical conductivity [33][34][35][36][37][38][39]. Furthermore, room temperature ferromagnetic properties are also achieved by doping with transition metals into ZnO nanostructures, which shows potential for increasing performance of sensing device and for future spintronics applications [40][41][42][43].…”