A nanowire structure includes successive crystalline nanowire segments formed over a semiconductor substrate. A first crystalline segment formed directly on the semiconductor substrate provides electrical isolation between the substrate and the second crystalline segment. Second and fourth crystalline segments are each formed from a p-type or an n-type semiconductor material, while the third crystalline segment is formed from a semiconductor material that is oppositely doped with respect to the second and fourth crystalline segments.

A quantum rod, a synthesis method of the quantum rod and a quantum rod display device are discussed. The quantum rod according to an embodiment includes a core, a first shell covering the core, and a second shell covering a side of the first shell. In the quantum rod, a first thickness of the first shell is greater than a second thickness of the second shell, and a first length of the first shell is smaller than a second length of the second shell.

It is an object of the present invention to provide a semiconductor nanoparticle having an excellent durability, and a dispersion liquid and a film, each of which uses the semiconductor nanoparticle. The semiconductor nanoparticle according to the present invention includes a core containing a Group III element and a Group V element, in which the nanoparticle contains carbon, oxygen, and sulfur, as detected by X-ray photoelectron spectroscopy, has peak A located at 2800 cm.sup.1 to 3000 cm.sup.1, peak B located at 1000 cm.sup.1 to 1200 cm.sup.1, and peak C located at 2450 cm.sup.1 to 2650 cm.sup.1, as detected by Fourier transform infrared spectroscopy, and contains a ligand having two or more mercapto groups.

A nanowire structure includes successive crystalline nanowire segments formed over a semiconductor substrate. A first crystalline segment formed directly on the semiconductor substrate provides electrical isolation between the substrate and the second crystalline segment. Second and fourth crystalline segments are each formed from a p-type or an n-type semiconductor material, while the third crystalline segment is formed from a semiconductor material that is oppositely doped with respect to the second and fourth crystalline segments.

A coated quantum dot is provided wherein the quantum dot is characterized by having a solid state photoluminescence external quantum efficiency at a temperature of 90 C. or above that is at least 95% of the solid state photoluminescence external quantum efficiency of the semiconductor nanocrystal at 25 C. Products including quantum dots described herein are also disclosed.

Techniques for achieving band gap grading in CZTS/Se absorber materials are provided. In one aspect, a method for creating band gap grading in a CZTS/Se absorber layer includes the steps of: providing a reservoir material containing Si or Ge; forming the CZTS/Se absorber layer on the reservoir material; and annealing the reservoir material and the CZTS/Se absorber layer under conditions sufficient to diffuse Si or Ge atoms from the reservoir material into the CZTS/Se absorber layer with a concentration gradient to create band gap grading in the CZTS/Se absorber layer. A photovoltaic device and method of forming the photovoltaic device are also provided.

Halometallate-capped semiconductor nanocrystals and methods for making the halometallate-capped semiconductor nanocrystals are provided. Also provided are methods of using solutions of the halometallate-capped semiconductor nanocrystals as precursors for semiconductor film formation. When solutions of the halometallate ligand-capped semiconductor nanocrystals are annealed, the halometallate ligands can act as grain growth promoters during the sintering of the semiconductor nanocrystals.

Photovoltaic devices based on an Ag.sub.2ZnSn(S,Se).sub.4 (AZTSSe) absorber and techniques for formation thereof are provided. In one aspect, a method for forming a photovoltaic device includes the steps of: coating a substrate with a conductive layer; contacting the substrate with an Ag source, a Zn source, a Sn source, and at least one of a S source and a Se source under conditions sufficient to form an absorber layer on the conductive layer having Ag, Zn, Sn, and at least one of S and Se; and annealing the absorber layer. Methods of doping the AZTSSe are provided. A photovoltaic device is also provided.

A semiconductor nanoparticle dispersion is provided. The semiconductor nanoparticle including a plurality of semiconductor nanoparticles having a radius equal to or larger than an exciton Bohr radius; and a solvent dispersed with the plurality of semiconductor nanoparticles.

A coated quantum dot and methods of making coated quantum dots are provided.