Heterojunction diodes with hydrogenated amorphous carbon (a-C:H) and nitrogen doped amorphous carbon (a-C:H:N) films on p-type silicon were prepared by means of plasma enhanced chemical vapor deposition. The electronic and structural properties of the films are analyzed as a function of nitrogen doping as well as thermal treatment after deposition.. X-ray photoelectron spectroscopy valence band spectra reveal that the electronic structure of the prepared a-C:H:N films depends on thermal annealing. The nature of the heterojunction is confirmed by the rectifying current-voltage characteristic of the carbonaceous deposit/p-Si junction with a heterojunction structure showing a behavior dependent on the amount of both nitrogen concentration and thermal annealing. In particular, the photovoltaic effect is observed only from annealed a-C:H:N heterojunction structures. Raman spectroscopy performed on heterojunction diodes after thermal treatment indicates that this behavior is most likely due to an extended graphitization.
Effect of Thermal Annealing on the Electronic Properties of Nitrogen Doped Amorphous Carbon/p-Type Crystalline Silicon Heterojunction Diodes
VALENTINI, LUCA;ARMENTANO, ILARIA;KENNY, Jose Maria;
2003
Abstract
Heterojunction diodes with hydrogenated amorphous carbon (a-C:H) and nitrogen doped amorphous carbon (a-C:H:N) films on p-type silicon were prepared by means of plasma enhanced chemical vapor deposition. The electronic and structural properties of the films are analyzed as a function of nitrogen doping as well as thermal treatment after deposition.. X-ray photoelectron spectroscopy valence band spectra reveal that the electronic structure of the prepared a-C:H:N films depends on thermal annealing. The nature of the heterojunction is confirmed by the rectifying current-voltage characteristic of the carbonaceous deposit/p-Si junction with a heterojunction structure showing a behavior dependent on the amount of both nitrogen concentration and thermal annealing. In particular, the photovoltaic effect is observed only from annealed a-C:H:N heterojunction structures. Raman spectroscopy performed on heterojunction diodes after thermal treatment indicates that this behavior is most likely due to an extended graphitization.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.