Article and Method for Implementing Electronic Devices on a Substrate Using Quantum Dot Layers

Abstract

Novel use of a cladded quantum dot array layer serving as a waveguide channel by sandwiching it between two cladding layers comprised of lower index of refraction materials is described to form Si nanophotonic devices and integrated circuits. The photonic device structure is compatible with Si nanoelectronics using conventional, quantum dot gate (QDG), and quantum dot channel (QDC) FET based logic, memories, and other integrated circuits.

I claim: 
     
         1 . A nano-photonic waveguide comprising of three layers,
 a middle layer,   a top cladding layer,   a bottom cladding layer, and   wherein the middle layer having an effective index of refraction higher than those of the top and bottom cladding layers, and regions adjacent to it vertically as well as laterally,   said three layers are deposited on a substrate which is selected from Si, Ge, Si-on-Insulator (SOI), Si-on-sapphire (SOS), GaAs, InP, ZnSe, and LiNbO 3 ,   said middle waveguide layer serving as the waveguiding layer wherein photons are confined in the transverse and lateral directions by regions selected from one of lower index of refraction, a photonic band gap or photonic crystal structure comprising of two-dimensional or three-dimensional photonic crystal lattice, and   wherein two-dimensional photonic crystal structure comprises periodic columns of holes or lower index of refraction regions,   said middle layer, serving as the waveguiding layer, is composed of a first layer, a second layer, and a third layer, and   wherein the first layer comprises one or more layers of semiconductor selected from Si, Ge, SiGe, II-VI, and III-V, and   wherein second layer comprises one or more layers of array of cladded quantum dots, and   wherein third layer comprises one or more layers of semiconductor selected from Si, Ge, SiGe, II-VI, and III-V, and   wherein said second layer of middle layer comprising of quantum dot array having quantum dots with a core with diameter in the range of 3-6 nm and a cladding of higher energy gap and lower index of refraction material in the range of 0.5-1.5 nm, and   wherein said quantum dot core is selected from Si, Ge, combination of Si and Ge, II-VI and III-V semiconductors, and   said cladding on quantum dots are selected from SiOx, GeOx, II-VI and III-V materials, and   wherein layers of array of cladded quantum dots are deposited on said first layer of middle layer serving as waveguiding layer comprising a semiconductor with p-type conductivity, and the semiconductor layer is selected one from a single crystalline, a poly-crystalline, and an amorphous morphology,   and wherein the array of cladded quantum dots is deposited with third layer comprising of semiconductor layer with n-type conductivity, and the semiconductor layer is selected one from a single crystalline, a poly-crystalline, and an amorphous morphology, and   wherein the nano-photonic waveguide is formed laterally by removing one or more of columns of holes or low index of refraction regions forming the two-dimensional photonic crystal lattice or photonic bandgap hole lattice, and wherein removal of said columns creates one-dimensional line defects,   wherein optical parameters of middle layer serving as the waveguiding layer can be altered by applying an external voltage and associated electric field, and   said middle layer optical parameters include one of effective index of refraction, and coefficient of absorption at given light wavelength, and wherein optical parameters are dependent on relative core diameter, cladding thickness and the materials of quantum dots comprising the middle layer,   a top cladding layer deposited above the third layer of middle waveguide layer is one selected from SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials,   a bottom cladding layer below the first layer of said middle waveguide layer having its material selected from SiO 2 , Si3N4, SiON, and other lower index of refraction and higher energy gap materials,   wherein the first layer of middle waveguide layer is deposited on Si-on-insulator substrate (SOI), and wherein the Si layer in SOI substrate is p+-type crystalline layer, and wherein the insulator layer is SiO 2 , and wherein the insulator or SiO 2  layer is serving as the lower cladding layer,   said nano-photonic waveguide structure has a width and a length, and   wherein the width is determined by the lines of columns holes or low index of regions missing in the photonic band gap or photonic crystal structure lattice, and   wherein the external voltage is applied across the middle waveguide layer via a pair of layers selected from p-type first layer and n-type second layer pair, and p+-type Si crystalline layer of SOI substrate and n-semiconductor layer of third layer of middle waveguide layer pair,   wherein the polarity of applied voltage is positive on p+-type Si crystalline layer and negative on n-type second layer.   
     
     
         2 . The nano-photonic waveguide structure of  claim 1 , wherein the nano-photonic waveguide structure is configured to operate as an optical modulator,
 wherein the second layer of the middle layer, serving as the waveguiding layer,   comprises one or more array of cladded quantum dots is GeO x —Ge, and   wherein the first layer of said middle layer on which the said array layer is deposited is p-type amorphous Si, and   wherein the p-type amorphous Si layer is deposited on Si-on-insulator substrate (SOI), and   wherein the Si layer in SOI substrate is p+-type crystalline layer, and wherein the insulator layer is SiO 2 , and wherein the insulator or SiO 2  layer is serving as the lower cladding layer, and   wherein the cladded quantum dot array layer is deposited with third layer of said middle layer, and wherein the third layer is an n-type amorphous Si layer, and   wherein top of said n-type amorphous Si layer is deposited with an upper cladding layer selected from one of SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials,   wherein said third layer of n-type amorphous Si layer is comprised of two layers, one layer on top and adjacent to said array of cladded GeOx-Ge quantum dots is lower doped n-layer and the other layer on top is a heavily doped n+ layer,   and the and p+-type Si layer forming the Si layer of SOI substrate and n+ amorphous Si layer are biased to control the optical absorption and index of refraction in said array of GeOx-Ge quantum dot layer,   the light is coupled to the middle layer serving as the waveguiding layer from one end of the nano-photonic waveguide structure, and   wherein the optical modulation at radio frequencies (RF) is realized by the magnitude of positive bias applied between the p+ crystalline Si and n+ type amorphous Si layers in conjunction with a DC positive bias on which RF is superposed.   
     
     
         3 . The nano-photonic waveguide structure of  claim 1 , wherein the nano-photonic waveguide structure is configured to operate as an edge-emitting light source,
 wherein the middle waveguide layer includes one or more array of cladded quantum dots is GeO x —Ge, and   wherein the first layer of said middle layer on which the said array layer is deposited is p-type amorphous Si, and wherein the p-type amorphous Si layer is deposited on Si-on-insulator substrate (SOI), and wherein the Si layer in SOI substrate is p+-type crystalline layer, and wherein the insulator layer is SiO 2 , and wherein the insulator or SiO 2  layer is serving as the lower cladding layer, and   wherein the cladded quantum dot array layer is deposited with third layer of said middle layer, and   wherein said third layer of n-type amorphous Si layer is comprised of two layers, one layer on top and adjacent to said array of cladded GeOx-Ge quantum dots is lower doped n-layer amorphous Si and the other layer on top is a heavily doped n+ amorphous Si,   wherein top of said n-type amorphous Si layer is deposited with an upper cladding layer selected from one of SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials,   wherein said third layer of n-type amorphous Si layer is comprised of two layers, one layer on top and adjacent to said array of cladded GeOx-Ge quantum dots is lower doped n-type amorphous Si and the other layer on top of lower doped layer is a heavily doped n+ amorphous layer, and   wherein deposited on top of said n+ amorphous layer is an upper cladding layer selected from one of SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials,   wherein p+-type crystalline Si layer comprising the SOI substrate and n+ amorphous Si layer in said third layer of middle layer serving as the waveguiding layer are biased to control the optical absorption and index of refraction in the GeOx-Ge quantum dot layer, and   wherein the two parallel facets of the nano-photonic waveguide structure serves as the reflecting mirror forming the cavity, and their separation is the cavity length, and   wherein the light is emitted from the middle waveguide layer from at least one of two facets forming the cavity in nano-photonic waveguide structure,   wherein the light emission is coherent and is controlled by the magnitude of positive bias applied between the p+ crystalline Si layer and n+ type amorphous Si layer.   
     
     
         4 . The nano-photonic waveguide structure of  claim 3 , wherein the nano-photonic waveguide structure is configured to operate as an edge-emitting light source,
 wherein the two parallel facets of the nano-photonic waveguide structure serving as the reflecting mirror forming the cavity are replaced by two-dimensional photonic crystal structure with columns of holes serving as the reflector of light, and   wherein separation of the two two-dimensional photonic crystal structure forms the length of the cavity.   
     
     
         5 . The nano-photonic waveguide structure of  claim 2 , wherein the nano-photonic waveguide structure is configured to operate as an optical modulator and an edge-emitting laser,
 wherein the optical modulator and the edge-emitting laser are integrated on a single substrate,   wherein the second layer of the middle layer serving as the waveguiding layer comprises one or more layers of array of GeO x —Ge cladded quantum dots, and   wherein the first layer of the said middle layer on which said array of cladded quantum dots is deposited is p-type amorphous Si, and   wherein the p-type amorphous Si layer is deposited on Si-on-insulator substrate (SOI), and wherein the Si layer in SOI substrate is p+-type crystalline layer, and wherein the insulator layer is SiO 2 , and wherein the insulator or SiO 2  layer is serving as the lower cladding layer, and   wherein cladded quantum dot array layer is deposited with third layer of middle layer, and   wherein said third layer is comprised of two layers, one layer on top and adjacent to said array of cladded GeOx-Ge quantum dots is lower doped n-type amorphous Si and the other layer on top of lower doped n-type amorphous Si layer is a heavily doped n+ type amorphous layer, and   wherein deposited on top of said n+ amorphous layer is an upper cladding layer selected from one of SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials, and   wherein etching techniques are used to divide the middle layer serving as the waveguiding layer and the top cladding layer into a first segment and a second segment,   wherein the first segment is etched to reveal two facets perpendicular to the waveguide, and wherein the two facets forming the laser cavity, and the second segment serving as the optical modulator,   wherein the first segment and the second segments have a common bottom electrodes and two separate upper electrical contacts, and where in the upper contact is formed on n+ type amorphous Si layer of said third layer of middle layer,   and the and p+-type Si layer forming the SOI substrate and n+ amorphous Si layer are biased independently in the two said segments to control the optical absorption or gain and index of refraction in the GeO x —Ge quantum dot layer,   wherein the light is emitted from the middle waveguide layer from one end of the nano-photonic waveguide structure, and wherein in the two parallel facets of the waveguides serves as the reflecting mirror forming the cavity in first segment,   wherein the light emission and laser output is governed by the magnitude of positive bias applied between the p+ crystalline Si layer and n+ type amorphous Si layer in first segment, and   wherein the light is coupled to the second segment, and   wherein the second segment having its own bias serves as optical modulator.   
     
     
         6 . The nano-photonic waveguide structure of  claim 1 , wherein the nano-photonic waveguide structure is configured to operate as an optical photodetector,
 wherein the second layer of the middle layer, serving as the waveguiding layer, comprises one or more array of cladded quantum dots is GeO x —Ge, and   wherein the first layer of said middle layer serving as the waveguiding layer on which the said array layer is deposited is p-type amorphous Si, and   wherein the p-type amorphous Si layer is deposited on Si-on-insulator substrate (SOI), and   wherein the Si layer in SOI substrate is p+-type crystalline layer, and wherein the insulator layer is SiO 2 , and wherein the insulator or SiO 2  layer is serving as the lower cladding layer, and   wherein the cladded quantum dot array layer is deposited with third layer of said middle layer, and wherein the third layer is an n-type amorphous Si layer, and   wherein top of said n-type amorphous Si layer is deposited with an upper cladding layer selected from one of SiO 2 , Si 3 N 4 , SiON, and other lower index of refraction and higher energy gap materials,   wherein said third layer of n-type amorphous Si layer is comprised of two layers, one layer on top and adjacent to said array of cladded GeOx-Ge quantum dots is lower doped n-layer and the other layer on top is a heavily doped n+ layer,   and the and p+-type Si layer forming the Si layer of SOI substrate and n+ amorphous Si layer are biased to control the optical absorption and index of refraction in said array of GeOx-Ge quantum dot layer, and   wherein light to be detected is coupled to the middle layer serving as the waveguiding layer from one end of the nano-photonic waveguide structure, and   wherein the optical absorption is realized by the magnitude of bias applied between the p+ crystalline Si and n+ type amorphous Si layers.   
     
     
         7 . A nano-photonic waveguide structure configured to operate as at least one of an optical modulator, an optical photodetector, and a light emitting source, the nano-photonic waveguide structure comprising:
 a substrate, wherein said nano-photonic waveguide structure is realized on the substrate which is selected from Si, Ge, Si-on-Insulator (SOI), Si-on-sapphire (SOS), GaAs, InP, ZnSe, and LiNbO 3 , and   wherein the semiconductor layer selected one from Si, Ge, SiGe, GaAs, InP, ZnSe, is used to construct electronic devices selected one from field-effect transistors, bipolar junction transistors, and   wherein the substrate hosts both nano-photonic waveguide structure based devices, and electronic devices and integrated circuits.