Photodiode having quantum dot light absorption layer

Patent metadata

Field	Value
Publication number	US-10923612-B2
Application number	US-202016944904-A
Country	US
Kind code	B2
Filing date	Jul 31, 2020
Priority date	Apr 20, 2017
Publication date	Feb 16, 2021
Grant date	Feb 16, 2021

Abstract

A photodiode comprising a photoactive spinel oxide layer is described. This photoactive spinel oxide layer forms a contact with both a light absorption layer of quantum dots, quantum wires, or quantum rods, and an inorganic substrate layer. In some embodiments, the inorganic substrate layer and the photoactive spinel oxide layer form an isotype junction. Methods of characterizing the photodiode are provided and demonstrate commercially relevant electrical and optoelectronic properties, particularly the ability to operate as a photodetector with a high photosensitivity. An economical process for preparing the photodiode is provided as well as applications.

First claim

The invention claimed is:

1. A photodiode, comprising:
an ohmic contact having a first work function;
an inorganic substrate layer in continuous contact with the ohmic contact;
a photoactive layer in continuous contact with the inorganic substrate layer;
a light absorption layer in continuous contact with the photoactive layer; and
a top electrode in contact with the light absorption layer, the top electrode having a second work function;
wherein the inorganic substrate layer comprises a semiconductor;
wherein the light absorption layer is made of an absorption composition comprising 70-95 wt % of quantum dots of at least one material selected from the group consisting of lead sulfide (PbS), lead selenide (PbSe), lead telluride (PbTe), cadmium selenide (CdSe), cadmium sulfide (CdS), and cadmium telluride (CdTe), with the remaining portion of the absorption composition a polymer matrix;
wherein the photoactive layer consists of ZnFe 2 O 4 nanowires in N 2 , the ZnFe 2 O 4 nanowires present at 80-90 vol % relative to a total volume of the photoactive layer;
wherein the ZnFe 2 O 4 nanowires have widths of 35-45 nm and lengths of 170-350 nm;
wherein all ZnFe 2 O 4 nanowires are physically adsorbed to the inorganic substrate layer and to the light absorption layer;
wherein the inorganic substrate layer and the photoactive layer are both p-type semiconductors forming an isotype junction between each other; and
wherein the second work function is higher than the first work function.

2. The photodiode of claim 1 , wherein the inorganic substrate layer has a thickness of 200-600 μm.

3. The photodiode of claim 1 , wherein the photoactive layer has a thickness of 20-250 nm.

4. The photodiode of claim 1 , wherein the light absorption layer has a thickness of 10-100 nm.

5. The photodiode of claim 1 , wherein the top electrode is aluminum.

6. The photodiode of claim 1 , wherein the inorganic substrate layer has a resistivity of 1-10 Ω·cm.

7. The photodiode of claim 1 , which has a barrier height of 0.5-1.25 eV.

8. The photodiode of claim 1 , which has a photoresponsivity of 0.10-0.40 A/W.

9. The photodiode of claim 1 , which has a photosensitivity defined as the ratio of illuminated current to dark current of 6000-7500 at a bias of 5.0-8.0 V.

Assignees

• Univ King Abdulaziz

Inventors

• Swelm Wageh
• Yakuphanoglu Fahrettin
• Al-Ghamdi Ahmed A
• Al-Turki Yusuf Abdulaziz

Classifications

• H10F77/1437

  Quantum wires or nanorods · CPC title

• H10F77/211

  for photovoltaic cells · CPC title

• H10F77/206

  for devices having potential barriers · CPC title

• H10F77/123

  comprising only Group II-VI materials, e.g. CdS, ZnS or HgCdTe · CPC title

• H10F71/00

  Manufacture or treatment of devices covered by this subclass (patterning processes to connect thin photovoltaic cells in integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/33; manufacture or treatment of encapsulations or containers for integrated devices, or assemblies of multiple devices, having photovoltaic cells H10F19/80; manufacture or treatment of integrated devices, or assemblies of multiple devices, comprising at least one element in which radiation controls the flow of current H10F39/00) · CPC title