Two-terminal electronic devices and their methods of fabrication
Two-terminal electronic devices, such as photodetectors, photovoltaic devices and electroluminescent devices, are provided. The devices include a first electrode residing on a substrate, wherein the first electrode comprises a layer of metal; an I-layer comprising an inorganic insulating or broad band semiconducting material residing on top of the first electrode, and aligned with the first electrode, wherein the inorganic insulating or broad band semiconducting material is a compound of the metal of the first electrode; a semiconductor layer, preferably comprising a p-type semiconductor, residing over the I-layer; and a second electrode residing over the semiconductor layer, the electrode comprising a layer of a conductive material. The band gap of the material of the semiconductor layer, is preferably smaller than the band gap of the I-layer material. The band gap of the material of the I-layer is preferably greater than 2.5 eV.
1. A two-terminal X-ray or high energy radiation detector comprising:
(a) a first electrode comprising a conductive material;
(b) an I-layer comprising an inorganic insulating or a broad band semiconducting material over the first electrode, wherein the inorganic insulating or the broad band semiconducting material is configured to transport electrons and block holes and has a band gap of at least 2.5 eV;
(c) a semiconductor layer or a stack of semiconductor layers over the I-layer,
wherein the semiconductor layer comprises:
(i) a first sublayer in contact with the I-layer comprising a material selected from the group consisting of an amorphous selenium, PbO, CdI, CdTe and HgI; and
(ii) a second sublayer comprising a p-type semiconductor over the first sublayer, wherein a band gap of the p-type semiconductor of the second sublayer is greater than a band gap of the material of the first sublayer; and
(d) a second electrode over the semiconductor layer or the stack, wherein at least one of the first and second electrodes is transparent.
2. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the first electrode comprises a metal selected from the group consisting of Ti, Ta, Zn, In, Sn, Ga, Zr, and Y and an alloy comprising any of these metals.
3. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the first electrode comprises a metal or a metal alloy and wherein the inorganic insulating or the broad band semiconducting material is a compound of the metal or of the metals of the metal alloy of the first electrode.
4. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the p-type semiconductor sublayer comprises a material selected from the group consisting of TPD, NPB, polymers comprising TPD, polymers comprising NPB, PFO, MoO, NiO, NiN and SiC.
5. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the first electrode is transparent to X-ray or high energy radiation.
6. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the second electrode is transparent to X-ray or high energy radiation.
7. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the p-type semiconductor sublayer comprises a material selected from the group consisting of MoO, NPB, and PPV.
8. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the first semiconductor sublayer comprises amorphous selenium.
9. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the inorganic insulating or the broad band semiconducting material is selected from the group consisting of ZnO, TiO 2 , and Ta 2 O 5 .
10. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the first semiconductor sublayer comprises amorphous selenium and the p-type semiconductor sublayer comprises MoO.
11. The two-terminal X-ray or high energy radiation detector of claim 1 , wherein the second electrode comprises ITO or AlZnO.
12. An array for X-ray sensing or high energy radiation sensing comprising a plurality of imaging pixels, wherein each imaging pixel of the detector array comprises the detector of claim 1 .
13. A two-terminal device comprising:
(a) a first electrode comprising a conductive material;
(b) an I-layer comprising an inorganic insulating or a broad band semiconducting material over the first electrode, wherein the inorganic insulating or the broad band semiconducting material is configured to transport electrons and block holes and has a band gap of at least 2.5 eV;
(c) a semiconductor layer or a semiconductor layer stack, the semiconductor layer comprising two sublayers, wherein the first sublayer is in contact with the I-layer and comprises a material selected from the group consisting of an organic semiconductor, CuO, PbS, CuInSe, CuInS, CuInGaSe, selenium, nanoparticles comprising at least one of PbS, PbSe, CdSe, and CdS, and a blend comprising any of these materials, and wherein the second sublayer comprises a p-type semiconductor configured for conducting holes and blocking electrons, wherein a band gap of the p-type semiconductor of the second sublayer is greater than a band gap of the material of the first sublayer; and
(d) a second electrode over the semiconductor layer or the stack, wherein at least one of the first and second electrodes is transparent, and wherein the two-terminal device is a visible light and/or IR detector or a photovoltaic device.
14. The two-terminal device of claim 13 , wherein the organic semiconductor in the first sublayer is selected from the group consisting of PPV, MEHPPV, P3HT, PTB7, PCPDTBT, PTZBTTT-BDT, PDDTT, and PCBM.
15. The two-terminal device of claim 13 , wherein the conductive material of the first electrode is a metal selected from the group consisting of Ti, Ta, Zn, In, Sn, Ga, Zr, Y and a metal alloy comprising any of these metals.
16. The two-terminal device of claim 13 , wherein the conductive material of the first electrode is a metal or a metal alloy, and wherein the inorganic insulating or a broad band semiconducting material of the I-layer is an oxide of the metal or of the metals of the alloy of the first electrode.
17. The two-terminal device of claim 13 , wherein the p-type semiconductor in the second sublayer comprises a material selected from the group consisting of TPD, NPB, polymers comprising TPD, polymers comprising NPB, PFO, MoO, NiO, NiN and SiC.
18. The two-terminal device of claim 13 , wherein the first electrode is transparent in the visible and/or infrared wavelength range.
19. The two-terminal device of claim 13 , wherein the second electrode is transparent in the visible and/or infrared wavelength range.
20. The two-terminal device of claim 13 , wherein the second electrode is transparent in the visible and/or infrared wavelength range and comprises a material selected from the group consisting of TCO, organic conductor, a thin layer of metal, and a thin layer of metal alloy.
21. A detector array comprising a plurality of imaging pixels, wherein each pixel comprises the two-terminal device of claim 13 .
22. An X-ray or high energy radiation detector comprising the two-terminal device of claim 13 and a scintillator.
23. An X-ray or high energy radiation detector array comprising a plurality of imaging pixels, wherein each pixel comprises the two-terminal device of claim 13 , and a scintillator.
24. The X-ray or high energy radiation detector array of claim 23 , wherein the scintillator is a sheet covering the plurality of imaging pixels.
25. The X-ray or high energy radiation detector of claim 1 , wherein the inorganic insulating or the broad band semiconducting material is a metal oxide having a bandgap of at least 2.5 eV.
26. The two-terminal device of claim 13 , wherein the inorganic insulating or the broad band semiconducting material is a metal oxide having a bandgap of at least 2.5 eV.
27. The two-terminal device of claim 13 , wherein the two-terminal device is a visible light detector and/or an IR detector.