Effect of hydrogen peroxide treatment on the characteristics of Pt Schottky contact on n-type ZnO

Abstract

We report on the formation of good Pt Schottky contacts on the Zn-terminated n-type ZnO (0001) surfaces (∼2×1017cm−3) using surface treatment with a hydrogen peroxide solution. The Pt contacts on organic solvent-cleaned ZnO (0001) show leaky behavior with a high leakage current of ∼−0.05A under −5V reverse bias voltage, whereas the hydrogen peroxide-treated contacts show Schottky behavior with very low leakage current of ∼−6.5×10−8A under −5V reverse bias voltage. Schottky barrier heights estimated from current-voltage and capacitance-voltage characteristics are 0.89 and 0.93eV, respectively. Room-temperature photoluminescence results show that the hydrogen peroxide treatment is fairly effective in removing deep-level defects near the ZnO surface region. In addition, the preliminary deep-level transient spectroscopy result is also presented.

One-dimensional ZnO nanostructures: Solution growth and functional properties

“…In addition to Pt, ZnO has been reported to form Schottky diodes with a variety of metals, such as Ag [532], Au [533], Pd [534], and Ni [534]. Surface treatment can effectively improve the diode performance [535,536]. The Pt coated tip was grounded and had a zero potential.…”

Interface trap characterization and electrical properties of Au-ZnO nanorod Schottky diodes by conductance and capacitance methods

“…4 A stable and good quality rectifying metal contact on the n-ZnO surface is crucial for many optoelectronic applications and remains a challenge despite numerous recent investigations. [4][5][6][7] The realization of high quality Schottky contacts on ZnO nanostructures seems to be difficult because of the interface states, the surface morphology, hydroxide surface contamination, and the subsurface defects, which all play important roles in the electrical properties of these contacts. 4 In recent years, a number of process methodologies have been developed for the fabrication of reproducible high quality Schottky contacts on ZnO nanostructures, but controversies remain with regard to the Schottky barrier height and the ideality factor of the ZnO Schottky contacts.…”

Role of near-surface states in ohmic-Schottky conversion of Au contacts to ZnO

“…In particular, fabrication of stable and rectifying metal contacts to ZnO remains a challenge despite numerous recent investigations. [1][2][3][4][5][6][7][8][9][10][11][12] A number of studies have addressed various possible fundamental mechanisms affecting Schottky barrier ͑SB͒ performance in ZnO, 1,5,9-13 but none have considered the role of both the surface and subsurface. Thus, while several studies have proposed that surface morphology, hydroxide ͑OH͒, and carbon surface contamination play a dominant role, none have considered the role of subsurface defects and impurities that could alter local carrier concentrations, depletion widths, and tunneling.…”