PLZT thin film capacitors apparatus with enhanced photocurrent and power conversion efficiency and method thereof

Patent metadata

Field	Value
Publication number	US-10957807-B2
Application number	US-201815957340-A
Country	US
Kind code	B2
Filing date	Apr 19, 2018
Priority date	Apr 19, 2017
Publication date	Mar 23, 2021
Grant date	Mar 23, 2021

Abstract

The exemplified systems, and method thereof, includes PLZT thin film (Pb0.95La0.05Zr0.54Ti0.46O3) paired with a bottom metal and top transparent conductive oxide, that forms a capacitor structure with enhanced photocurrent and power conversion efficiency. The exemplified systems use metal electrode (platinum) as bottom electrode and a transparent oxide (Indium Tin Oxide—ITO) as the top electrode. In some embodiments, the capacitor structure are used in a solar cells, ultraviolet sensors, or UV indexing sensors. In some embodiments, the capacitor structure are energy generation or for medical diagnostics (e.g., for skin care application).

First claim

What is claimed is:

1. An apparatus comprising:
a silicon-based substrate comprising Si and SiO 2 ;
a bottom layer coupled to the substrate, the bottom layer forming an electrode that comprises a material that includes, in part, a material selected from the group consisting of Al, Au, Pt, LaNiO 3 , LaAlO 3 , LSMO, LSCO, RuO x Nb:SrTiO 3 , ITO, and a combination thereof;
a seed layer coupled to the bottom layer, the seed layer comprising a material selected from the group consisting of Pb x TiO 3 , where x=1.0, 1.05, 1.1, or 1.2; PbO; PbZrO 3 ; LaNiO 3 ; TiO x where x≤2; SrTiO 3 ; SrRuO 3 ; La x Sr 1-x CoO 3 , where 0<x<1; and La x Sr 1-x MnO 3 where 0<x<1;
a thin film layer coupled to the seed layer, the thin film layer substantially spanning the bottom layer and comprising a lanthanum-doped lead zirconate titanate thin film material selected from the group consisting of PbZr 1-x Ti x O 3 -based device or a (Pb 1-y La y )(Zr x Ti 1-x )O 3 -based device, where 0≤x≤1 and 0≤y≤0.1; and
an array of top electrodes that collectively form a top layer over the thin film layer so as to form a plurality of capacitors, each of the top electrodes comprising a transparent oxide layer.

2. The apparatus of claim 1 , wherein the lanthanum-doped lead zirconate titanate thin film material comprises Pb 0.95 La 0.05 Zr 0.54 Ti 0.46 O 3 .

3. The apparatus of claim 2 , wherein the substrate further comprises TiO 2 .

4. The apparatus of claim 1 , wherein the transparent oxide layer comprises transparent indium tin oxide (ITO).

5. The apparatus of claim 1 , wherein each formed capacitor of the plurality of capacitors has a light-to-electricity conversion efficiency of at least 0.05%, and wherein each of formed capacitor of the plurality of capacitors forms a solar cell.

6. The apparatus of claim 1 , wherein each formed capacitor of the plurality of capacitors has a photocurrent density J sc of at least −6.83×10 −5 A/cm 2 (Amp per cm 2 ), and wherein each of the formed capacitor of the plurality of capacitors forms an ultraviolet sensor.

7. The apparatus of claim 6 , wherein the thin film layer is configured as a sensing layer for the ultraviolet sensor.

8. The apparatus of claim 1 , wherein the bottom layer comprises a composite selected from the metal consisting of Au, Pt, and a combination thereof and an oxide group consisting of LaNiO 3 LaAlO 3 , LSMO, LSCO, RuO x , Nb:SrTiO 3 , ITO, and a combination thereof.

9. The apparatus of claim 1 , wherein each formed capacitor of the plurality of capacitors has an operational spectral wavelength range that, at least, spans a range consisting of between about 315 nm and about 400 nm, between about 280 nm and about 315 nm, and between about between 200-800 nm.

10. The apparatus of claim 1 , wherein the array of top electrodes comprises a plurality of structures that form gaps thereamong so as to form the plurality of capacitors, wherein the plurality of capacitors include a first top electrode of the array that forms a capacitor with a second top electrode of the array.

11. The apparatus of claim 1 , wherein two or more electrodes of the array are electrically linked by a connection member, wherein the two or more electrodes forming a capacitor with a portion of the bottom layer across a portion of the thin film layer or the two or more electrodes forming a capacitor with another electrode of the array.

12. The apparatus of claim 1 , further comprising an ultraviolet-light indexing device comprising:
a display; and
a sensing element configured to respond to UV radiation, the sensing element comprising the substrate, the bottom layer, the thin film layer, and the top electrode; and
electronic circuitry coupled to an output of the sensing element to receive an electric output, or a signal derived therefrom, generated from the sensing element in response to exposure of the sensing element by the UV radiation, the electronic circuitry being coupled to the display and configured to present an index parameter generated from with the electric output.

13. The apparatus of claim 12 , wherein the apparatus is configured as a wearable or is embedded in an article of clothing.

14. The apparatus of claim 13 , further comprising:
a wireless transceiver, the wireless transceiver being coupled to the electronic circuitry and being configured to transmit to generated index parameter to a computing device.

15. The apparatus of claim 12 , further comprising:
a processor; and
a memory, the memory having instructions stored thereon, wherein execution of the instructions, cause the processor to:
calculate an index parameter from a parameter derived from the electric output,
wherein the instructions, when executed by the processor, further cause the processor to, cause presentation of the index parameter or one of a plurality of pre-defined messages, wherein each of the plurality of pre-defined messages is associated with a corresponding UV index tier to which the index parameter is compared.

16. The apparatus claim 15 , wherein the instructions, when executed by the processor, further cause the processor to cause presentation, at the display or at a remote computing device, of one of a plurality of pre-defined messages, each of the plurality of pre-defined messages being associated with an amount of sun protection.

17. The apparatus of claim 15 , wherein the instructions, when executed by the processor, further cause the processor to cause presentation, at the display or at a remote computing device, of one of a plurality of pre-defined messages including a first message directed to presence, or degree of, UV-A, and a second message directed to presence, or degree, of UV-B.

18. The apparatus of claim 15 , wherein the electronic circuitry comprises:
an amplifier circuit;
an analog-to-digital conversion circuit;
a processor; and
a memory, the memory having instructions stored thereon, wherein execution of the instructions, cause the processor to calculate an index parameter from a parameter derived, via the analog-to-digital convert circuit; from the electric output.

19. A method of generating electric energy, comprising:
exposing a solar cell to electromagnetic radiation, the solar cell comprising:
a silicon-based substrate comprising Si and SiO 2 ;
a bottom layer coupled to the silicon-based substrate, the bottom layer forming an electrode that comprises a material that includes, in part, a material selected from the group consisting of Al, Au, Pt, LaNiO 3 , LaAlO 3 , LSMO, LSCO, RuO x , Nb:SrTiO 3 ITO, and a combination thereof;

a seed layer coupled to the bottom layer, the seed layer comprising a material selected from the group consisting of Pb x TiO 3 , where x=1.0, 1.05, 1.1, or 1.2; PbO; PbZrO 3 ; LaNiO 3 , TiO x where x≤2; SrTiO 3 ; SrRuO 3 ; La x Sr 1-x CoO 3 , where 0<x<1; and La x Sr 1-x MnO 3 where 0<x<1;
a thin film layer coupled to the seed layer, the thin film layer substantially spanning the bottom layer and comprising a lanthanum-doped lead zirconate titanate thin film material selected from the group consisting of PbZr 1-x Ti x O 3 -based device or a (Pb 1-y La y )(Zr x Ti 1-x )O 3 -based device, where 0≤x≤1 and 0≤y≤0.1; and
a top electrode of an array of top electrodes that collectively form a top layer over the thin film layer so as to form a plurality of capacitors with the bottom layer, each of the top electrodes comprising a transparent oxide layer,
wherein the exposure causes generation of a photocurrent from the thin film layer.

20. A method of sensing ultra-v

Assignees

• Univ Alabama

Inventors

• Kotru Sushma
• Nampoori Harshan V
• Batra Vaishali

Classifications

• G01J5/34

  using capacitors, e.g. pyroelectric capacitors · CPC title

• H10F77/247

  comprising indium tin oxide [ITO] · CPC title

• H10F30/227

  the potential barrier being a Schottky barrier · CPC title

• H10F30/222

  the potential barrier being a PN heterojunction · CPC title

• H10F30/10

  the devices being sensitive to infrared radiation, visible or ultraviolet radiation, and having no potential barriers, e.g. photoresistors · CPC title