| 1. |
|
|
| 2. |
- Kemerink, Martijn, et al.
(författare)
-
Low-temperature scanning-tunneling microscope for luminescence measurements in high magnetic fields
- 2001
-
Ingår i: Review of Scientific Instruments. - : American Institute of Physics (AIP). - 0034-6748 .- 1089-7623. ; 72:1, s. 132-135
-
Tidskriftsartikel (refereegranskat)abstract
- We have designed and built a low-temperature (1.3-4.2 K) scanning-tunneling microscope which is capable of collecting light that is generated in the tunneling region. Light collection is done by means of two fibers whose cleaved front is in close proximity (approximate to1 mm) to the tunneling region. The whole system can be operated in high magnetic fields (11 T) without loss of optical signal strength. As a demonstration, we measured the electroluminescence spectra of an InGaAs quantum well at various temperatures. At 4.2 K, we found an electron-to-photon conversion factor that is three orders of magnitude higher than at room temperature. (C) 2001 American Institute of Physics.
|
|
| 3. |
- Kemerink, Martijn, et al.
(författare)
-
Optical detection of ballistic electrons injected by a scanning-tunneling microscope
- 2001
-
Ingår i: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 86:11, s. 2404-2407
-
Tidskriftsartikel (refereegranskat)abstract
- We demonstrate a spectroscopic technique which is based on ballistic injection of minority carriers from the lip of a scanning-tunneling microscope into a semiconductor heterostructure. Ey analyzing the resulting electroluminescence spectrum as a function of tip-sample bias, both the injection barrier height and the carrier scattering rate, in the semiconductor can be determined. This technique is complementary to ballistic electron emission spectroscopy since minority instead of majority carriers are injected, which give the opportunity to study the carrier trajectory after injection.
|
|
| 4. |
- Kemerink, Martijn, et al.
(författare)
-
Optical detection of ballistically injected electrons in III/V heterostructures
- 2001
-
Ingår i: PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS, PTS I AND II. - : SPRINGER-VERLAG BERLIN. - 3540417788 ; , s. 819-820
-
Konferensbidrag (refereegranskat)abstract
- We present a novel spectroscopic technique which is based on the ballistic injection of minority carriers from the tip of an STM into a semiconductor heterostructure. By analyzing the resulting electro-luminescence spectrum as a function of tip-sample bias, both the injection barrier height and the carrier relaxation rate Gamma (s) after injection can be determined. From current dependent measurements we find that carrier trapping by impurities causes a significant non-radiative recombination channel at room temperature.
|
|
| 5. |
- Kemerink, Martijn, et al.
(författare)
-
Optical properties of a tip-induced quantum dot
- 2001
-
Ingår i: PROCEEDINGS OF THE 25TH INTERNATIONAL CONFERENCE ON THE PHYSICS OF SEMICONDUCTORS, PTS I AND II. - : SPRINGER-VERLAG BERLIN. - 3540417788 ; , s. 1183-1184
-
Konferensbidrag (refereegranskat)abstract
- We have performed optical spectroscopy measurements on an STM-tip-induced quantum dot. The dominant confinement in the (hole) quantum dot is in the direction parallel to the tip axis. Electron confinement is achieved by a sub-surface AlGaAs barrier. Current dependent measurements indicate that many-body interactions can cause spectral blue-shifts up to 75 meV.
|
|
| 6. |
- Kemerink, Martijn, et al.
(författare)
-
Spectrally resolved luminescence from an InGaAs quantum well induced by an ambient scanning tunneling microscope
- 1999
-
Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 75:23, s. 3656-3658
-
Tidskriftsartikel (refereegranskat)abstract
- Spectrally resolved scanning tunneling microscope-induced luminescence has been obtained under ambient conditions, i.e., at room temperature, in air, by passivating the sample surface with sulfur. This passivation turned out to be essential to suppress the local anodic oxidation induced by the tunneling current. From the dependence of the luminescence signal on tunneling current and voltage, we find that the passivation solution and post-passivation annealing temperature strongly modify the surface density of states (SDOS). More specifically, we found evidence that, after annealing at 400 degrees C, no SDOS is left above the bottom of the conduction band. For annealing at 200 degrees C, the SDOS is found to be extended up to 1.0 +/- 0.2 eV above the bottom of the conduction band. In all cases, the passivated (001) surface appears to be completely pinned. (C) 1999 American Institute of Physics. [S0003-6951(99)01949-X].
|
|
| 7. |
|
|
| 8. |
- Park, J, et al.
(författare)
-
Gene-Environment Interactions Relevant to Estrogen and Risk of Breast Cancer: Can Gene-Environment Interactions Be Detected Only among Candidate SNPs from Genome-Wide Association Studies?
- 2021
-
Ingår i: Cancers. - : MDPI AG. - 2072-6694. ; 13:10
-
Tidskriftsartikel (refereegranskat)abstract
- In this study we aim to examine gene–environment interactions (GxEs) between genes involved with estrogen metabolism and environmental factors related to estrogen exposure. GxE analyses were conducted with 1970 Korean breast cancer cases and 2052 controls in the case-control study, the Seoul Breast Cancer Study (SEBCS). A total of 11,555 SNPs from the 137 candidate genes were included in the GxE analyses with eight established environmental factors. A replication test was conducted by using an independent population from the Breast Cancer Association Consortium (BCAC), with 62,485 Europeans and 9047 Asians. The GxE tests were performed by using two-step methods in GxEScan software. Two interactions were found in the SEBCS. The first interaction was shown between rs13035764 of NCOA1 and age at menarche in the GE|2df model (p-2df = 1.2 × 10−3). The age at menarche before 14 years old was associated with the high risk of breast cancer, and the risk was higher when subjects had homozygous minor allele G. The second GxE was shown between rs851998 near ESR1 and height in the GE|2df model (p-2df = 1.1 × 10−4). Height taller than 160 cm was associated with a high risk of breast cancer, and the risk increased when the minor allele was added. The findings were not replicated in the BCAC. These results would suggest specificity in Koreans for breast cancer risk.
|
|
