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US 2014/0111241 A1Published application
Optical testing of a multi quantum well semiconductor device
AssigneeBrown University
InventorHumphrey J. Maris
Life of this patent
Estimating the term…
Abstract
A pump light pulse is generating a strain pulse in a sample that includes quantum wells. A signal is measured using a probe light pulse. The probe light pulse is delayed in relation to the pump light pulse. The signal derives from a change in an optical property of the sample, which optical property responds to the generated strain pulse. One may deduce parameters of interest of the sample, including the quantum wells, from the characteristics of the signal. For discerning between various components of the stress in the quantum wells a lead pump pulse, preceding the pump light, pulse my also be used. A system for the application of such methods is also disclosed.
Claims22
A method, comprising:
- accepting a sample, wherein said sample comprises quantum wells sandwiched in-between two semiconductor layers, wherein said sample has an optical property, and has a parameter of interest;
- creating a strain pulse inside said sample by directing a pump light pulse onto said sample and selecting the wavelength of said pump light pulse in such manner that said quantum wells absorb said pump light pulse whereby generating electron/hole pairs in said quantum wells, wherein said quantum wells are piezoelectric whereby said strain pulse is responsive to an electric field created by said electron/hole pairs, and wherein said optical property is responsive to said strain pulse;
- measuring a signal using a probe light pulse, wherein said probe light pulse is directed onto said sample with a time delay in relation to said pump light pulse, and said probe light pulse is responsive to said optical property, wherein said signal derives from a change in said optical property as function of said time delay, wherein said signal has an amplitude, an said amplitude is responsive to said electric field;
- and
- deriving said parameter of interest from a characteristic of said amplitude.
2 more elements
A method, comprising:
- accepting a sample, wherein said sample comprises quantum wells sandwiched in-between two semiconductor layers, wherein said sample has an optical property, and has a parameter of interest;
- creating a strain pulse inside said sample by directing a pump light pulse onto said sample and selecting the wavelength of said pump light pulse in such manner that said quantum wells absorb said pump light pulse, wherein said optical property is responsive to said strain pulse;
- measuring a signal using a probe light pulse, wherein said probe light pulse is directed onto said sample with a time delay in relation to said pump light pulse, and said probe light pulse is responsive to said optical property, wherein said signal derives from a change in said optical property as function of said time delay, and said signal comprises at least one periodicity;
- and
- deducing said parameter of interest from one or more of said at least one periodicity.
2 more elements
A system, comprising:
- a sample, wherein said sample comprises quantum wells sandwiched in-between two semiconductor layers, wherein said quantum wells are of a piezoelectric material, wherein said sample has an optical property, and has a parameter of interest;
- a pump light pulse, wherein said pump light pulse is directed onto said sample and has such wavelength that is absorbed by said quantum wells whereby capable of generating electron/hole pairs in said quantum wells and to create a strain pulse in said sample;
- an electric field created by said electron/hole pairs, wherein due to said piezoelectric material said strain pulse is responsive to said electric field, and wherein said optical property is responsive to said strain pulse;
- a probe light pulse, wherein said probe light pulse is directed onto said sample with a time delay in relation to said pump light pulse, and said probe light pulse is responsive to said optical property;
- a signal, wherein said signal is contained in said probe light pulse, wherein said signal derives from a change in said optical property as function of said time delay, wherein said signal has an amplitude, and said amplitude is responsive to said electric field;
- and
- wherein said parameter of interest is derivable from a characteristic of said amplitude.
4 more elements
A system, comprising:
- a sample, wherein said sample comprises quantum wells sandwiched in-between two semiconductor layers, wherein said sample has an optical property, and has a parameter of interest;
- a pump light pulse, wherein said pump light pulse is directed onto said sample and has such wavelength that is absorbed by said quantum wells and is capable to create a strain pulse in said sample, wherein said optical property is responsive to said strain pulse;
- a probe light pulse, wherein said probe light pulse is directed onto said sample with a time delay in relation to said pump light pulse, and said probe light pulse is responsive to said optical property;
- a signal, wherein said signal is contained in said probe light pulse, wherein said signal derives from a change in said optical property as function of said time delay, and said signal comprises at least one periodicity;
- and
- wherein said parameter of interest is derivable from one or more of said at least one periodicity.
3 more elements
Dependencies are inferred from the claim text.