A mode-locked laser injects pulses of minority carriers into a semiconductor sample. A microwave frequency comb is then generated by the currents formed in the movement of majority carriers native to the semiconductor and the injected minority carriers. These carriers move to cause dielectric relaxation in the sample, which can be used to determine carrier density within the sample. Measurements require close proximity of transmitter and receiver contacts with the sample and may profile a semi-conductor with a resolution of approximately 0.2 nm.

A mode-locked laser injects pulses of minority carriers into a semiconductor sample. A microwave frequency comb is then generated by the currents formed in the movement of majority carriers native to the semiconductor and the injected minority carriers. These carriers move to cause dielectric relaxation in the sample, which can be used to determine carrier density within the sample. Measurements require close proximity of transmitter and receiver contacts with the sample and may profile a semi-conductor with a resolution of approximately 0.2 nm.

Techniques, methods, devices, and compositions are disclosed that are useful in identifying and sequencing natural and synthetic, and modified and unmodified DNA, RNA, PNA, DNA/RNA nucleotides. The disclosed techniques, methods, devices, and compositions are useful in identifying various modifications, DNA/RNA damage, and nucleotide structure, using nanoelectronic quantum tunneling spectroscopy, which may be referred to as QM-Seq. The methods and compositions can include the use of a charged, smooth substrate for deposition of single stranded nucleotides and polynucleotide macromolecules, scanning the modified or unmodified DNA/RNA/PNA, comparing the electronic signatures of an unknown nucleobase against a database of electronic fingerprints of known nucleobases, including natural and synthetic, modified and unmodified nucleobases, and secondary/tertiary structure, obtained under the same or similar conditions, for example where the nucleobase is in an acidic environment.

Techniques, methods, devices, and compositions are disclosed that are useful in identifying and sequencing natural and synthetic, and modified and unmodified DNA, RNA, PNA, DNA/RNA nucleotides. The disclosed techniques, methods, devices, and compositions are useful in identifying various modifications, DNA/RNA damage, and nucleotide structure, using nanoelectronic quantum tunneling spectroscopy, which may be referred to as QM-Seq. The methods and compositions can include the use of a charged, smooth substrate for deposition of single stranded nucleotides and polynucleotide macromolecules, scanning the modified or unmodified DNA/RNA/PNA, comparing the electronic signatures of an unknown nucleobase against a database of electronic fingerprints of known nucleobases, including natural and synthetic, modified and unmodified nucleobases, and secondary/tertiary structure, obtained under the same or similar conditions, for example where the nucleobase is in an acidic environment.

A semiconductor carrier profiling method utilizes a scanning tunneling microscope and shielded probe with an attached spectrum analyzer to measure power loss of a microwave frequency comb generated in a tunneling junction. From this power loss and by utilizing an equivalent circuit or other model, spreading resistance may be determined and carrier density from the spreading resistance. The methodology is non-destructive of the sample and allows scanning across the surface of the sample. By not being destructive, additional analysis methods, like deconvolution, are available for use.

A mode-locked laser injects pulses of minority carriers into a semiconductor sample. A microwave frequency comb is then generated by the currents formed in the movement of majority carriers native to the semiconductor and the injected minority carriers. These carriers move to cause dielectric relaxation in the sample, which can be used to determine carrier density within the sample. Measurements require close proximity of transmitter and receiver contacts with the sample and may profile a semi-conductor with a resolution of approximately 0.2 nm.

An optical output system includes: a first laser that outputs first light which is a pulse laser in response to input of a first signal; a second laser that outputs second light which is a pulse laser in response to input of a second signal; and an arithmetic unit that inputs the first signal and the second signal to the first laser and the second laser, wherein the arithmetic unit repeatedly inputs the first signal and the second signal with switching a variable delay value, which is a difference between a timing to input the first signal to the first laser and a timing to input the second signal to the second laser, in a plurality of ways.

An optical output system includes: a first laser that outputs first light which is a pulse laser in response to input of a first signal; a second laser that outputs second light which is a pulse laser in response to input of a second signal; and an arithmetic unit that inputs the first signal and the second signal to the first laser and the second laser, wherein the arithmetic unit repeatedly inputs the first signal and the second signal with switching a variable delay value, which is a difference between a timing to input the first signal to the first laser and a timing to input the second signal to the second laser, in a plurality of ways.

A method of examining a sample (1) in a microscope equipped with at least one scanning tunneling tip (4), wherein tunneling current TC can be detected and wherein relative tip-to-sample planar coordinates xrel=xtipxsample and yrel=ytipysample are differences between corresponding tip and sample coordinates, wherein the following steps are performed above at least two surface points of the sample (1): placing the tip (4) successively above said surface points of the sample (1); above each of said surface points of the sample, performing a distance varying step (33) comprising varying the tip-to-sample distance D, and performing a time dependencies recording step (35), comprising recording time dependencies TC(t), xrel(t), yrel(t), D(t). Based on these time dependencies, four maps can be created from a single measurement: constant current map, constant height map, Local Density of States Topography map and potential barrier map.