1. A solar cell, comprising:
a semiconductor substrate having a front surface and a back surface, wherein the front surface of the semiconductor substrate has a plurality of nano-rods extending from the front surface, a height of the nano-rods is 0.005 to 20 \u03bcm, a width of the nano-rods is 0.005 to 5 \u03bcm, and a distance between the adjacent nano-rods is 0.005 to 5 \u03bcm;
a doping layer, disposed on a surface of the nano-rods;
a front anti-reflective layer covering the doping layer, wherein a material of the front anti-reflective layer is indium tin oxide;
a quantum well layer disposed on the back surface of the semiconductor substrate, the quantum well layer having at least one first doping region and at least one second doping region, wherein the first doping region and the second doping region have opposite conductivity types, the quantum well layer comprises a first polycrystalline silicon germanium (Si1-xGex) layer, and the value of x is 0\u2266x\u22661;
a first passivation layer, covering the first doping region of the quantum well layer, wherein the first passivation layer comprises a N-type doping passivation material and a first passivation material, and wherein the N-type doping passivation material is sandwiched between the first passivation material and the first doping region;
a second passivation layer, covering the second doping region of the quantum well layer and the N-type doping passivation material, wherein the second passivation layer comprises a P-type doping passivation material and a second passivation material, the P-type doping passivation material is sandwiched between the second passivation material and the second doping region; and
at least one first metal electrode and at least one second metal electrode contacting and passing through the P-type doping passivation material to be electrically connected to the first doping region and the second doping region of the quantum well layer, respectively.
2. The solar cell of claim 1, further comprising:
an auxiliary passivation layer disposed between the semiconductor substrate and the quantum well layer; and
a backside reflective layer, covering the first passivation layer and the second passivation layer.
3. The solar cell of claim 1, wherein the quantum well layer further comprises at least one second polycrystalline silicon germanium (Si1-yGey) alternatively stacked with the first polycrystalline silicon germanium (Si1-xGex), wherein 0\u2266x<1 and 0\u2266y<1.
4. The solar cell of claim 1, wherein the doping layer conformably covers the surface of nano-rods so that a plurality of spaces between the nano-rods are not fully filled.
5. The solar cell of claim 4, wherein the front anti-reflective layer conformably covers and contacts the doping layer so that the spaces between the nano-rods are not fully filled by the front anti-reflective layer.
6. A solar cell, comprising:
a semiconductor substrate having a front surface and a back surface, wherein the front surface of the semiconductor substrate has a plurality of nano-rods extending from the front surface, a height of the nano-rods is 3 to 20 \u03bcm, a width of the nano-rods is 0.1 to 5 \u03bcm, and a distance between the adjacent nano-rods is 0.1 to 5 \u03bcm;
a doping layer, disposed on a surface of the nano-rods;
a front anti-reflective layer covering the doping layer, wherein a material of the front anti-reflective layer comprises indium tin oxide, indium zinc oxide, aluminum tin oxide, aluminum zinc oxide, indium germanium zinc oxide, a stacked layer of at least two of the above materials, or a combination thereof;
a quantum well layer disposed on the back surface of the semiconductor substrate, the quantum well layer having at least one first doping region and at least one second doping region, wherein the first doping region and the second doping region have opposite conductivity types;
a first passivation layer, covering the first doping region of the quantum well layer, wherein the first passivation layer comprises a N-type doping passivation material and a first passivation material, and wherein the N-type doping passivation material is sandwiched between the first passivation material and the first doping region;
a second passivation layer, covering the second doping region of the quantum well layer and the N-type doping passivation material, wherein the second passivation layer comprises a P-type doping passivation material and a second passivation material, the P-type doping passivation material is sandwiched between the second passivation material and the second doping region; and
at least one first metal electrode and at least one second metal electrode contacting and passing through the P-type doping passivation material to be electrically connected to the first doping region and the second doping region of the quantum well layer, respectively.
7. The solar cell of claim 6, wherein the doping layer conformably covers the surface of nano-rods so that a plurality of spaces between the nano-rods are not fully filled.
8. The solar cell of claim 7, wherein the front anti-reflective layer conformably covers and contacts the doping layer so that the spaces between the nano-rods are not fully filled by the front anti-reflective layer.
The claims below are in addition to those above.
All refrences to claim(s) which appear below refer to the numbering after this setence.
1. A method, comprising:
defining a set of reference locations about a region of interest of a subject or object, which is identified in at least one image from a time sequence of images;
applying a motion model to a reference location of the set, wherein the motion model is indicative of a trajectory through the image sequence;
generating a set of group-wise registered images from the time sequence of images by concurrently registering the time sequence of images based on the model applied to the reference location of the set.
2. The method of claim 1, wherein the trajectory extends through the time sequence of image sequence.
3. The method of claim 1, wherein the trajectory estimates image-to-image motion of the reference location through the image sequence.
4. The method of claim 3, further comprising:
defining a set of sample points about the reference location; and
minimizing variability of transported image information based on the set of sample points.
5. The method of claim 4, wherein minimizing the variability includes minimizing an average variance of a grey value in a vicinity of the trajectory through the image sequence.
6. The method of claim 1, wherein the motion model is based on cyclic motion.
7. The method of claim 1, wherein the motion model includes one or more free parameters, and further including determining the one or more free parameters based on the images during registration.
8. The method of claim 1, further comprising propagating the region of interest through the group-wise registered image sequence.
9. The method of claim 1, wherein the motion model models at least one of a respiratory or a cardiac cycle.
10. The method of claim 1, wherein the group-wise registration is local to the region of interest.
11. A system, comprising:
a region of interest identifier that identifies a region of interest in at least one image in a series of images of a moving object;
a reference location identifier that identifies a plurality of reference locations about the region of interest;
a model bank that includes one or more models indicative of cyclical motion of the moving object; and
a registration component that group-wise registers the images based on a motion model from the model bank and the images by applying the motion model to the images at a reference location of the reference locations and concurrently registering the series of images, wherein the motion model is indicative of a cyclic trajectory through the series of images.
12. The system of claim 11, wherein the model includes at least one free parameter, and the registration component determines the free parameter based on the reference location.
13. The system of claim 12, further comprising:
a sample point identifier that identifies a plurality of sample points about a reference location, wherein the registration component minimizes a variability of transported image information for the reference location based on the plurality of sample points.
14. The system of claim 13, further comprising:
a region of interest propagator that propagates the region of interest through the registered image sequence.
15. The system of claim 11, wherein the registration mitigates gating artifact of pair-wise, anatomical model based image registration.
16. A computer readable storage medium containing instructions which, when executed by a computer, cause the computer to perform the act of:
obtaining a time series image sequence of a moving object or subject;
obtaining a motion model indicative of motion of the object or subject;
defining a region of interest in an image of the image sequence; and
propagating the region of interest to one or more images in the image sequence based on a group-wise registration of the images with the motion model, wherein the registration includes applying a cyclic trajectory motion model through the time series image sequence from a reference location about the region of interest and concurrently registering the images.
17. The computer readable storage medium of claim 16, wherein the motion model models at least one of a respiratory or a cardiac cycle.
18. The computer readable storage medium of claim 17, further containing instructions which, when executed by the computer, cause the computer to perform the act of: determining a free parameter of the motion model based on the reference location.
19. The computer readable storage medium of claim 18, further containing instructions which, when executed by the computer, cause the computer to perform the acts of: defining a set of sample points about the reference location and minimizing a variability of transported image information for the reference location based on the set of sample points.
20. The computer readable storage medium of claim 18, wherein the region of interest is located nearer a middle of the image sequence and propagated in both directions through image sequence.