3 eV) which could reduce the energy barrier for carrier transport and also effectively avoid parasitic absorption. However,
doped Si-NCs embedded in a SiN x matrix (Si-NCs/SiN x ) have not received much attention. In this work, we present initial fabrication and characterization results of Si heterojunction solar cells JNK-IN-8 price using P-doped Si-NCs/SiN x films as emitters. The P-doped Si-NCs/SiN x films were prepared by electron cyclotron resonance chemical vapor deposition (ECRCVD) followed by high-temperature annealing, and the influence of the chemical composition (N/Si ratio) on their physical properties was investigated. The photovoltaic properties of the fabricated heterojunction devices were also examined as a function of the N/Si composition ratio in the P-doped Si-NCs/SiN x films. Methods Fifty-nanometer-thick, homogeneous Si-rich silicon nitride (SRN) films containing phosphorus were deposited by a homemade ECRCVD system
on single-side polished p-type (100) single crystalline Si (sc-Si) substrates with a thickness of 675 μm and a resistivity in the range of 5 to 20 Ω cm. Before placing into the deposition AC220 chamber, Si substrates were cleaned with acetone and rinsed in deionized water followed by removal of native oxide on Si wafers using a diluted HF dip (5%). The mixed SiH4, N2, Ar, and PH3 gases were then introduced into the deposition chamber at 10 mTorr for film growth. The applied microwave power and the filipin substrate temperature were kept on
700 W and 200°C, respectively. In order to study the influence of the Si/N ratio on film properties, both SiH4 and PH3 flow rates were kept constant during film growth, while the gas mix ratio (R c) defined as N2/SiH4 was varied in the range 0.73 ≤ R c ≤ 0.83. The formation of Si-NCs in as-deposited SRN films was selleck compound carried out by post-growth annealing in a quartz tube furnace at 950°C in N2 ambient. Samples with a 1 cm × 1 cm area were used for subsequent fabrication of heterojunction solar cells. Aluminum films deposited by electron gun evaporation were used as contact electrode layers in the solar cells. The front contact on top of the Si-NCs/SiN x film was defined by a shadow mask during Al deposition, while the rear contact covered the full back area of the cell. After metallization, the samples were heated at 500°C for 3 min to improve the electrical properties of the contacts. For the characterization, the bonding configurations of the Si-NCs/SiN x films were identified by X-ray photoelectron spectroscopy (XPS). Micro-Raman spectroscopy and transmission electron microscopy (TEM) were used to investigate the crystallization behavior in SRN films after post-growth annealing. Fused quartz wafers were used as substrates for Raman studies to avoid the signal contribution from Si substrates during Raman measurements. X-ray diffraction (XRD) was used to evaluate the Si-NC size of annealed samples.