1. Study of Thermal and Optical Characteristics of Selected Optical Detectors
H. P. Lamichhane and A. G. U. Perera
Department of Physics and Astronomy,
Georgia State University, Atlanta, Georgia 30303
12/08/05

12. Photovoltaic Effect

17. Noise in Semiconductor Detectors
1. Johnson Noise
2. g-r noise found in photoconductors
3. Shot noise found in photodiodes
4. 1/f noise

18. Johnson Noise
PN = k T B
VN = (4 k T R B)1/2
And
IN = (4 k T B / R)1/2

23. Spectral Response

30. Figure 1.

31. Figure 2

32. The noise measurement of the sample 79 is shown figure 4.

33. a
Figure 4. a. Noise current in sample 79 at 30 K. b. Noise
current in sample 79 at 03 K. in the active region. c. Noise
current in sample 79 at 20 K. in the active region.

34. b
Figure 4. a. Noise current in sample 79 at 30 K. b. Noise
current in sample 79 at 03 K. in the active region. c. Noise
current in sample 79 at 20 K. in the active region.

35. c
Figure 4. a. Noise current in sample 79 at 30 K. b. Noise
current in sample 79 at 30 K. in the active region. c. Noise
current in sample 79 at 20 K. in the active region.

36. Figure 5
Figure 5 shows the Arrhenious calculation of the sample V0262.

37. Figure 6
Figure 6 and Figure 7a show activation energy calculation of the same sample.

38. b. a.
Figure 7 a. Activation energy of the sample V0262 F,
b. Corresponding threshold wavelength of the same sample.

39. Figure 8 shows the responsivity of the sample 476.

40. Conclusion
Though optical detectors are faster, we need to improve the responsivity of the detector to detect small signals from biomolecules.

41. Thank You