Growth, optical, and electrical properties of single-crystalline Si-CdSe biaxial p-n heterostructure nanowires

Single-crystalline Si-CdSe biaxial p-n heterostructure nanowires (NWs) have been grown via chemical vapor deposition method and characterized. The Si and CdSe subnanowires have diameters of about 30 and 60 nm, respectively, and grow along the [(2) over bar1 (1) over bar] and [0001] directions, respectively. Room-temperature photoluminescence (PL), Raman-scattering, and electrical transport measurements were made on single Si-CdSe biaxial heterostructure NWs. Strong CdSe band-edge emission peaked around 710 nm together with a broad emission centered at 600 nm is observed in the PL spectra. Intense sharp longitudinal optical phonon modes from both CdSe and Si are observed in Raman-scattering spectra. The resistivities, carrier concentrations, and carrier mobilities of single CdSe NW and Si subnanowire are estimated. A good rectification characteristic is observed in the I-V curve of Si-CdSe biaxial NW, which confirms that the Si-CdSe biaxial NW is a p-n heterostructure.