Detectivity (D*)
Specific detectivity from NEP, area, and bandwidth. D* = √(A·Δf) / NEP
Responsivity (M = 1)
0.480 A/W
E_g = 1.127 eV from λ_c
Detector D*
2.616e+12 cm·Hz^½/W
J_d = 1.000e-7 A/cm²; dark-current shot noise dominates; area-independent
NEP (system)
3.749e-11 W/√Hz
Shot Noise (multiplied dark)
1.790e-11 A
Thermal Noise
1.799e-8 A
System D* (incl. load R_L)
2.668e+9 cm·Hz^½/W
Load Johnson noise dominates: grows as √A at fixed I_d
Detector: D* = ℛ·M / √(2·q·J_d·M²·F + 4·k·T / R₀A), J_d = I_d / A
System: D* = √(A·Δf) / NEP, NEP = i_n / (ℛ·M)
ℛ = η·q·λ / (h·c) for λ ≤ λ_c = h·c/E_g, else 0
i²_shot = 2·q·I_d·M²·F·Δf, i²_thermal = 4·k·T·Δf / R_L
I_d(T) ∝ n_i ∝ T^1.5·exp(−E_g/2kT) (generation) or ∝ n_i² (diffusion), scaled from the entered I_d at the entered T
Model and references
Textbook approximation. A standard approximation from the literature (for example paraxial, plane-wave or Gaussian-beam), valid within the range the page states. About the tiers
Constant quantum efficiency up to the cutoff λ_c = hc/E_g. Detector D* from the dark-current density J_d = I_d/A (multiplied shot noise 2q·J_d·M²·F) and the zero-bias R₀A (Johnson 4kT/R₀A): area-independent. System D* adds the load's Johnson noise instead of R₀A; with I_d fixed and load noise dominant it grows as √A. The default R₀A is illustrative. The temperature chart scales I_d as n_i or n_i² and R₀A inversely, with a fixed band gap and constant responsivity, the load held at the entered temperature.
- Dereniak E. L., Boreman G. D. (1996). Infrared Detectors and Systems. Wiley. Ch. 5: responsivity, noise-equivalent power and specific detectivity D* = √(A·Δf)/NEP.
- Rogalski A. (2003). Infrared detectors: status and trends. Prog. Quantum Electron. 27, 59–210. Photodiode D* = ℛ(4kT/R₀A + 2qJ)^−½. doi:10.1016/S0079-6727(02)00024-1
- Saleh B. E. A., Teich M. C. (1991). Fundamentals of Photonics. Wiley. §17.5 Noise in photodetectors: shot noise 2qīB and circuit noise. doi:10.1002/0471213748
- Sze S. M., Ng K. K. (2007). Physics of Semiconductor Devices, 3rd ed. Wiley. p–n junction depletion capacitance (abrupt m = 1/2, linearly graded m = 1/3), n_i(T), generation and diffusion currents. doi:10.1002/0470068329