Mist fabrication of quantum dot devices
An example quantum dot (QD) device comprises a QD layer on a substrate, and may be fabricated by aerosol deposition, for example by mist deposition. An example approach includes providing a liquid precursor including QDs dispersed in a liquid carrier, generating a mist of droplets of the liquid precursor, directing the droplets towards the substrate so as to form a liquid precursor film on the substrate, and removing the liquid carrier from the liquid precursor film to form the quantum dot layer on the substrate. Example devices include multi-color QD-LED (light emitting diode) displays, and other devices.
1. A process for fabricating a semiconductor quantum dot layer on a substrate, the semiconductor quantum dot layer being an emissive layer of a multi-color display, the process comprising:
providing a liquid precursor including semiconductor quantum dots dispersed in a liquid carrier;
generating a mist of droplets of the liquid precursor, the mist of droplets comprising droplets each including a suspension of one or more of the semiconductor quantum dots in the liquid carrier;
directing the mist of droplets towards the substrate, so as to form a liquid precursor film on the substrate;
using a shadow mask to pattern the liquid precursor film; and
removing the liquid carrier from the patterned liquid precursor film so as to form the semiconductor quantum dot layer on the substrate,
the semiconductor quantum dot layer being patterned by the shadow mask to form the emissive layer of the multi-color display,
the multi-color display being a QD-LED (quantum dot light emitting diode) display.
2. The process of claim 1 , further comprising using an atomizer to generate droplets of the liquid precursor.
3. The process of claim 1 , the droplets having a diameter distribution with a peak diameter approximately equal to or less than 5 microns.
4. The process of claim 3 , the diameter distribution having a peak diameter approximately equal to or less than 1 micron.
5. The process of claim 3 , the diameter distribution having a peak diameter approximately equal to 0.25 microns.
6. The process of claim 1 , further comprising
aligning apertures within the shadow mask with electrodes on the substrate.
7. The process of claim 1 , the droplets being conveyed into a deposition chamber by a stream of carrier gas.
8. The process of claim 7 ,
the deposition chamber including a shower head through which the droplets enter the deposition chamber, and a field screen,
the liquid precursor film having a deposition rate on the substrate,
the deposition rate being adjustable by an electrical potential between the field screen and the substrate.
9. The process of claim 8 , the stream of carrier gas having a inlet speed for entering the deposition chamber,
the deposition rate being substantially independent of the inlet speed.
10. The process of claim 1 , the substrate including a plurality of electrodes.
11. The process of claim 10 , the semiconductor quantum dot layer being formed selectively on the plurality of electrodes.
12. The process of claim 11 , the substrate further including a second plurality of electrodes,
the process further including selectively forming a second semiconductor quantum dot layer on the second plurality of electrodes.
13. The process of claim 1 , the semiconductor quantum dot layer having a layer thickness,
the semiconductor quantum dots having a quantum dot diameter,
the layer thickness being between 1 and 5 times the quantum dot diameter.
14. The process of claim 13 , the semiconductor quantum dot layer having a layer thickness variation less than the quantum dot diameter.
15. A process for fabricating a semiconductor quantum dot layer on a substrate, the semiconductor quantum dot layer being an emissive layer of a multi-color display, the process comprising:
providing a liquid precursor including semiconductor quantum dots dispersed in a liquid carrier;
generating a mist of droplets of the liquid precursor, the mist of droplets comprising droplets each including a suspension of one or more of the semiconductor quantum dots in the liquid carrier;
directing the mist of droplets towards the substrate, so as to form a liquid precursor film on the substrate;
using a shadow mask to pattern the liquid precursor film; and
removing the liquid carrier from the patterned liquid precursor film so as to form the semiconductor quantum dot layer on the substrate,
the semiconductor quantum dot layer having a layer thickness,
the quantum dots having a quantum dot diameter,
the layer thickness being between 1 and 5 times the quantum dot diameter,
the semiconductor quantum dot layer being patterned by the shadow mask to form the emissive layer of the multi-color display,
the multi-color display being a QD-LED (quantum dot light emitting diode) display.
16. The process of claim 15 , the semiconductor quantum dot layer having a layer thickness variation less than the quantum dot diameter.