Structural and Optical Properties of CdTe Thin Films Deposited Using RF Magnetron Sputtering

Role of CdTe Interface Structure on CdS/CdTe Photovoltaic Device Performance

Glancing angle deposition (GLAD) of CdTe can produce a cubic, hexagonal, or mixed phase crystal structure depending upon the oblique deposition angles (Φ) and substrate temperature. GLAD CdTe films are prepared at different Φ at room temperature (RT) and a high temperature (HT) of 250 °C and used as interlayers between the n-type hexagonal CdS window layer and the p-type cubic CdTe absorber layer to investigate the role of interfacial tailoring at the CdS/CdTe heterojunction in photovoltaic (PV) device performance. The Φ = 80° RT GLAD CdTe interlayer and CdS both have the hexagonal structure, which reduces lattice mismatch at the CdS/CdTe interface and improves electronic quality at the heterojunction for device performance optimization. The device performance of HT CdS/CdTe solar cells with Φ = 80° RT with 50 to 350 nm thick GLAD CdTe interlayers is evaluated in which a 250 nm interlayer device shows the best device performance with a 0.53 V increase in open-circuit voltage and fill-factor product and a 0.73% increase in absolute efficiency compared to the HT baseline PV device without an interlayer.

Efficient anchoring of nanostructured cadmium selenide on different kinds of carbon nanotubes

We report a method for the efficient anchoring of cadmium selenide (CdSe) nanoparticles on the surface of different types of multi-walled carbon nanotubes (purified, N-doped, O-doped and exfoliated). Characterization using different types of electron microscopies (SEM, STEM, and TEM), energy dispersive spectroscopy (EDS) and x-ray diffraction showed well anchored CdSe nanoparticles (NP) on the nanotube surfaces, NP shapes and sizes varied with temperature and other synthesis conditions, and formed with good yields. The method here reported does not require previous activation of the carbon nanotube surface by chemical functionalization, nor the use of organic solvents, and the reaction proceeded in aqueous solutions, making this process simpler and more environmentally friendly than others.

Arrayed CdTeMicrodots and Their Enhanced Photodetectivity via Piezo-Phototronic Effect

In this paper, a photodetector based on arrayed CdTe microdots was fabricated on Bi coated transparent conducting indium tin oxide (ITO)/glass substrates. Current-voltage characteristics of these photodetectors revealed an ultrahigh sensitivity under stress (in the form of force through press) while compared to normal condition. The devices exhibited excellent photosensing properties with photoinduced current increasing from 20 to 76 μA cm-2 under stress. Furthermore, the photoresponsivity of the devices also increased under stress from 3.2 × 10-4 A/W to 5.5 × 10-3 A/W at a bias of 5 V. The observed characteristics are attributed to the piezopotential induced change in Schottky barrier height, which actually results from the piezo-phototronic effect. The obtained results also demonstrate the feasibility in realization of a facile and promising CdTe microdots-based photodetector via piezo-phototronic effect.