Electricaland Optical Properties of InN/Si Heterostructure
- PDF / 126,873 Bytes
- 6 Pages / 595 x 842 pts (A4) Page_size
- 49 Downloads / 206 Views
L11.26.1
ELECTRICAL AND OPTICAL PROPERTIES OF InN/Si HETEROSTRUCTURE K. Mizuo, T. Yamaguchi, Y. Saito, T. Araki and Y. Nanishi Dept. of Photonics, Ritsumeikan Univ., 1-1-1 Noji-Higashi, Kusatsu, Shiga, 525-8577 Japan
ABSTRACT Single crystalline InN films were grown on Si substrates by radio-frequency plasma-excited molecular beam epitaxy. Electrical property of InN/Si heterojunction was investigated. We obtained rectifying characteristics in n-InN/p-Si heterostructure for the first time. Forward I-V characteristics were affected by both the buffer layer deposition and the nitridation process. Strong photoluminescence peaks for both single crystalline and polycrystalline InN films grown on the Si substrates were observed at around 0.8 eV, which were smaller than the previous reported PL emission peak of around 1.9 eV.
INTRODUCTION Nitride semiconductors are promising materials for photonics and electronics. However, growth and characterization as well as device application of InN have not been widely studied compared with other nitrides. This is because of the difficulty to obtain high quality InN due to its low dissociation temperature and high equilibrium vapor pressure. Thus, among nitride semiconductors, physical properties of InN have not been well known up to now enough to be applied to photonic and electronic devices. For example, InN has been understood to have a direct bandgap of 1.9 eV. However, it is reported very recently that the bandgap energy of InN is less than 1 eV [1-3]. Furthermore, high quality InN films with high electron mobility have been obtained on a sapphire substrate [4-7]. These results are getting us to explore new application fields of nitrides semiconductor. Growth of nitride semiconductors on a Si substrate is also an important issue since using Si as a substrate can overcome several restrictions. For example, a Si substrate is easily obtained at high quality and low cost, and has a variety specification we asked for. In the case of InN growth, the lattice mismatch for a Si (111) substrate (7.6 %) is much smaller than that for a sapphire (0001) substrate (25.4 %). Furthermore, device application using hetero junction of nitride semiconductors on Si has a prospect in semiconductor technology. Some possible devices applying this combination are monolithic integration devices, tandem-type solar cells [8], light emitting diode and so on. In the case of nitride semiconductors, since N atoms are not electrically active in Si, the Si side of the interface is expected to show p-type due to possibly diffused group-III atoms from the nitride semiconductor. Therefore, hetero junction composed of InN and Si is expected to be applicable to pn junction. Recently, Yoshimoto et al. reported fabrication and characterization of InN/Si heterostructure [9,10]. They found that no rectifying characteristic was observed in the heterojunction of n+-InN/p-Si due to a large number of interface states. These results suggest that quality of the InN films grown on Si should be improved for achieving the applica
Data Loading...
