Academic Profile : Faculty

Prof Hilmi Volkan Demir.jpg picture
Prof Hilmi Volkan Demir
Professor, School of Electrical & Electronic Engineering
Professor, School of Physical & Mathematical Sciences
Professor, School of Materials Science & Engineering (Courtesy Appointment)
  • Nanoantenna Light-Emitting Devices
  • Next-Generation Ultra low-Cost High-Efficiency Eco-Friendly Lamps
US 2017/0345640 A1: Field Emission Light Source (2019)
Abstract: The present invention generally relates to a field emission light source and specifically to a miniaturized field emission light source that is possible to manufacture in large volumes at low cost using the concept of wafer level manufacturing, i.e. a similar approach as used by IC's and MEMS. The invention also relates to a lighting arrangement comprising at least one field emission light source. The field emission light source comprises: a field emission cathode (106) comprising a plurality of nanostructures (104) formed on a substrate; an electrically conductive anode structure (108) comprising a first wavelength converting material (118) arranged to cover at least a portion of the anode structure, wherein the first wavelength converting material is configured to receive electrons emitted from the field emission cathode and to emit light of a first wavelength range, and means for forming an hermetically sealed and subsequently evacuated cavity (106) between the substrate of the field emission cathode and the anode structure, including a spacer structure (302, 110) arranged to encircle the plurality of nano structures, wherein the substrate for receiving the plurality of nanostructures is a wafer (102′).

US 2016/0141542 A1: Organic Light Emitting Device (2019)
Abstract: According to one embodiment, an organic light emitting device is described including a first light emitting unit, a second light emitting unit and a charge generation layer wherein the second light emitting unit is stacked over the first light emitting unit and is connected to the first light emitting unit by means of the charge generation layer and wherein the charge generation layer includes an electron transport layer, a transition metal oxide layer arranged over the electron transport layer and a diffusion suppressing layer arranged between the electron transport layer and the transition metal oxide layer to separate the electron transport layer from the transition metal oxide layer.

US 2016/0307959 A1: Light-Emitting Device And Method Of Forming The Same (2018)
Abstract: A light-emitting device may include an active layer. The light-emitting device may include a first semiconductor layer of a first conductivity type. The first semiconductor layer may be in physical contact with the active layer. The light-emitting device may also include a second semiconductor layer of a second conductivity type. The second semiconductor layer may be in physical contact with the active layer and opposite the first conductive layer. The light-emitting device may further include a first electrode in physical contact with a first side of the first semiconductor layer. The light-emitting device may additionally include a second electrode in physical contact with a second side of the first semiconductor layer. The second side of the first semiconductor layer may be different from the first side of the first semiconductor layer. The light-emitting device may also include a third electrode in physical contact with the second semiconductor layer.

US 2016/0254472 A1: Perovskite Thin Films Having Large Crystalline Grains (2018)
Abstract: The invention relates generally to perovskite materials, and in particular, to perovskite thin films having large crystalline grains. Methods of forming the perovskite thin films are disclosed herein. The perovskite thin films find particular use in photovoltaic applications.

US 2015/0325742 A1: Method Of Fabricating Semiconductor Devices (2016)
Abstract: Vertical high power LEDs are the technological choice for the application of general lighting due to their advantages of high efficiency and capability of handling high power. However, the technologies of vertical LED fabrication reported so far involve the wafer-level metal substrate substitution which may cause large stress due to the mismatch between metal substrate and LED layer. Moreover, the metal substrate has to be diced to separate LED dies which may cause metal contamination and thus increase the leakage current. These factors will lower the yield of LED production and increase the cost as well. The present invention is to disclose a novel method for the fabrication of GaN vertical high power LEDs and/or a novel method for the fabrication of GaN vertical high power LEDs which is compatible to mass production conditions. The novelty of the invention is that the island metal plating is conducted with the help of pattern formation techniques. Due to the small area of the islands, the stress generated between LED layer and metal islands is much less significant. Furthermore, due to the island metal plating and through the application of temporary supporting carriers the LED dies will be separated at the end of the fabrication process automatically or simply by applying slight mechanical stress or stretching the adhesive tape. This advantage avoids the metal dicing step and reduces the possibility of metal contamination and leakage current generation. Therefore, high yield and low cost will be realized using this novel method in LED production.

US 2015/0179872 A1: A Light-Emitting Device (2016)
Abstract: A light emitting device comprising a plurality of current spreading layers including a first P doped layer, a first N doped layer and a second P doped layer, wherein the N doped layer having a doping level and thickness configured for substantial depletion or full depletion.

US 2014/0306179 A1: A Light Emitting Device (2016)
Abstract: A light-emitting device comprising: a hole injection layer, an electron injection layer, and a composite emitter layer including a soft material exciton donor and exciton acceptor nanoparticles substantially dispersed within the exciton donor matrix, wherein electrons from the electron injection layer and holes from the hole injection layer generate excitons in the exciton donor matrix, and the primary mechanism of photon generation at the nanoparticles is substantially through non-radiative energy transfer of the generated excitons directly into the nanoparticles.
Fellowships & Other Recognition
Fellow of IEEE, Fellow of Optica (formerly, OSA)