1. A seedless method for forming a semiconductor-graphene hybrid:
forming a graphene sheet on a support to form a supported graphene sheet having a graphene face;
exposing said supported graphene sheet to a solution comprising a semiconductor metal ion at a temperature below 100\xb0 C. and under ambient air pressure for a time so that said semiconductor grows on said graphene sheet, and wherein said exposing occurs without seeding said graphene sheet.
2. The method of claim 1 wherein said exposing step comprises orienting said supported graphene sheet face-up in said solution.
3. The method of claim 1 wherein said exposing step comprises orienting said supported graphene sheet face-down in said solution.
4. The method of claim 1 wherein said exposing step comprises floating said supported graphene sheet on the surface of said solution comprising said semiconductor metal ion, wherein said graphene face is facing down so that said semiconductor grows on said face of said graphene sheet.
5. The method of claim 1 wherein said forming step comprises growing a graphene sheet on a substrate using chemical vapor deposition; spin-coating said support onto said graphene sheet; and removing said substrate.
6. The method of claim 1 wherein said forming step comprise the steps of growing a graphene sheet on a copper or nickel substrate using chemical vapor deposition; spin-coating a polymethylmethacrylate, polyvinylpyrrolidone, or polystyrene support onto said graphene sheet; and removing said copper or nickel substrate.
7. The method of claim 1 wherein said graphene sheet comprises one to two layers of graphene.
8. The method of claim 1 wherein said semiconductor comprises a metal oxide grown on said graphene sheet.
9. The method of claim 1 wherein said semiconductor forms nanostructures or microstructures comprising rods on said graphene sheet.
10. A seedless method for forming a semiconductor-graphene hybrid:
forming a graphene sheet on a support to form a supported graphene sheet having a graphene face;
exposing said supported graphene sheet to a solution comprising a semiconductor metal ion at a temperature below 100\xb0 C. for a time so that said semiconductor grows on said graphene sheet, and wherein said exposing occurs without seeding said graphene sheet, and
wherein said semiconductor forms nanostructures or microstructures comprising rods on said graphene sheet, and
wherein said exposing step comprises orienting said supported graphene sheet face-up in said solution, wherein said rods are generally horizontally aligned on said graphene.
11. The method of claim 9 wherein said exposing step comprises floating said supported graphene sheet on the surface of said solution comprising said semiconductor metal ion such that said graphene face is facing down in solution, and wherein said rods are generally vertically aligned on said graphene.
12. The method of claim 9 wherein said rods have a hexagonal cross section.
13. The method of claim 1 wherein said semiconductor comprises zinc oxide, copper oxide or combinations thereof.
14. The method of claim 1 wherein said solution has a pH of about 8 to 11.
15. The method of claim 1 wherein said solution comprises zinc ions, and said semiconductor-graphene hybrid comprises a graphene sheet having zinc oxide nanorods andor microrods.
16. The method of claim 1 wherein said exposing occurs for about 1 to 15 hours.
17. The method of claim 1 wherein said exposing occurs at a temperature of about 60 to 100\xb0 C.
18. The method of claim 1 wherein said support comprises polymethylmethacrylate, polyvinylpyrrolidone, polystyrene, or combinations thereof.
19. A seedless method for forming a semiconductor-graphene hybrid:
forming a graphene sheet on a support to form a supported graphene sheet having a graphene face;
exposing said supported graphene sheet to a solution comprising a semiconductor metal ion at a temperature below 100\xb0 C. for a time so that said semiconductor grows on said graphene sheet, and wherein said exposing occurs without seeding said graphene sheet, and wherein said exposing step comprises orienting said supported graphene sheet in a first orientation for a first period of time and then orienting said supported graphene sheet in a second configuration for a second period of time.
20. The method of claim 1 wherein said exposing step comprises exposing said supported graphene sheet to an aqueous solution comprising semiconductor metal cations, and wherein said metal cations react with hydroxyl groups from solution which are attached to surface defects on said supported graphene sheet.
21. The method of claim 20 wherein said supported graphene sheet is floated on the surface of said aqueous solution comprising said semiconductor metal cations.
22. The method of claim 1 wherein said method results in a semiconductor-graphene hybrid having an electrical conductivity that is substantially the same as said graphene sheet alone.
23. A semiconductor-graphene hybrid prepared by the method comprising:
forming a graphene sheet on a support to form a supported graphene sheet having a graphene face:
exposing said supported graphene sheet to a solution comprising a semiconductor metal ion at a temperature below 100\xb0 C. and under ambient air pressure for a time so that said semiconductor grows on said graphene sheet, and wherein said exposing occurs without seeding said graphene sheet.
24. A seedless method for forming a semiconductor-graphene hybrid comprising exposing a supported graphene sheet to an aqueous basic solution comprising transition metal ions at a temperature below 100\xb0 C. and under ambient pressure for a time to provide a semiconductor comprising an oxide of the transition metal ions grown on said graphene sheet, and wherein said exposing occurs without seeding said graphene sheet.
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 for receiving a frequency modulated signal, characterized in that
the radio frequency signal is mixed into a low-frequency signal,
the falling and rising edges of said low-frequency, modulated signal are detected,
a second signal is formed on the basis of said edge detection, the frequency of the second signal being twice the frequency of said low-frequency signal, and
said second signal is frequency detected to form a demodulated signal.
2. A method according to claim 1, characterized in that the processing of the frequency modulated signal includes the following steps:
the antenna signal is filtered with a band pass filter,
the signal is amplified,
the signal is down-converted in at least two branches with phase-shifted local oscillator signals LO,
the signal is low pass filtered and
amplified.
3. A method according to claim 1, characterized in that the processing of the frequency modulated signal also includes the following steps:
the signals are phased in at least two branches,
the signals are summed into one branch,
the signal is low pass filtered,
amplified and
demodulated.
4. A method according to claim 1, characterized in that the demodulation of the frequency modulated signal includes the following steps:
the modulated signal is divided into two branches, the first one for the detection of the rising signal edge and the second one for the detection of the falling signal edge;
the rising edge of the modulated signal is detected in the first branch,
the modulated signal is inverted and the rising edge of the inverted, modulated signal is detected in the second branch, and
the signals processed in the first and the second branch are combined.
5. A method according to claim 1, characterized in that the demodulation of the frequency modulated signal includes the following steps:
the modulated signal is divided into two branches, the first one for the detection of the rising signal edge and the second one for the detection of the falling signal edge,
the rising edge of the modulated signal is detected in the first branch,
the falling edge of the modulated signal is detected in the second branch, and
the signals processed in the first and the second branch are combined.
6. A method according to claim 1, characterized in that pulses of a predetermined length are formed on the basis of said edge detection, and the pulses are summed to form said second signal.
7. An arrangement for receiving a frequency modulated signal, characterized in that it comprises
means for mixing a radio frequency signal into a low-frequency signal, and demodulator means, which comprise
means for detecting the falling and rising edges of said low-frequency signal,
means for forming a second signal on the basis of said edge detection, the frequency of the second signal being twice the frequency of said low-frequency signal, and
means for the frequency detection of said second signal.
8. An arrangement according to claim 7, characterized in that it comprises mixers and 0 and 90 phase shifters for mixing the signal of at least two branches with the signal of the local oscillator LO.
9. An arrangement according to claim 7, characterized in that it comprises 0 and 90 phase shifters, an adder and a demodulator of the frequency modulated signal.
10. An arrangement according to claim 7, characterized in that the demodulator of the frequency modulated signal comprises two branches, of which the upper branch comprises a pulse detector for detecting the rising edge of the frequency modulated signal to be demodulated, and the lower branch comprises an inverter and a pulse detector connected in series for detecting the falling edge of the frequency modulated signal to be demodulated, and an adder that combines the branches.
11. An arrangement according to claim 7, characterized in that the demodulator of the frequency modulated signal comprises two branches, of which the upper branch comprises a pulse detector for detecting the rising edge of the frequency modulated signal to be demodulated, and the lower branch comprises a pulse detector active on the falling edge of the signal for detecting the falling edge of the frequency modulated signal to be demodulated, and an adder that combines the branches.
12. An arrangement according to claim 7, characterized in that the means for detecting the edges of a low-frequency signal comprise a pulse generator for forming a pulse of a specified length as triggered by the edge of a low-frequency signal.
13. A mobile station, characterized in that it comprises an arrangement according to claim 7 for receiving a frequency modulated signal.