ISSN:
1089-7550
Source:
AIP Digital Archive
Topics:
Physics
Notes:
The penetration depths of protons in the (0001¯) face of ZnO produced by 100- and 400-eV hydrogen-ion bombardment are studied by three methods: calibrated argon-ion sputtering, calibrated etching, and space-charge capacitance measurements in the ZnO/electrolyte system. For the 100-eV implantation, the latter method provides unequivocal support to our previous conclusion that the protons, acting as fully ionized donors, penetrate only to a depth of 10–20 A(ring) below the surface. The narrow space-charge layer so produced, having surface electron densities of up to 2 × 1014 cm−2, constitutes a quantized, two-dimensional electron gas system. In the 400-eV implanted surface, the proton penetration depth is considerably larger. In this case an approximate depth profile could be derived from the combined measurements. It consists of a Gaussian distribution, peaked about 40 A(ring) below the surface with a standard deviation of some 80 A(ring). However, some 10% of the implanted protons are found to penetrate much deeper, being distributed up to 1000 A(ring) or more below the surface. For 100-eV implanted surfaces, similarly large penetration depths were observed, but the percentage of the deep lying protons is less than 1%. Such huge penetration depths arise most probably from a channeling mechanism.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1063/1.336510
