Master equation approach of classical noise in intersubband detectors

Electronic transport in intersubband detectors is investigated theoretically and experimentally. Within the framework of inter–Wannier-Stark levels electron scattering, consistent dark current and low-frequency noise expressions are obtained through the resolution of the two first moments of a master equation for classical particles. In particular, the formulation of noise bridges over the vision of uncorrelated Johnson and shot contributions. Theoretical predictions are compared to measurements for five quantum well detectors, either photovoltaic or photoconductive, whose detection wavelength span from $8\mu \text{m}$ to $17\mu \text{m}$. Quantitative agreement with experiment is found for a broad range of biases and temperatures. Correlation effects are discussed and proven to either reduce or enhance the noise.

Figure 1

Dark noise currents for the QCD at $8\mu \text{m}$ measured at 90 K. The bench noise has been offset for clarity reasons, but is actually at $1.37\times {10}^{-13}\text{A}{\text{Hz}}^{-1/2}$.

Figure 2

Top right: dark current model and measurements for the QCD detecting at $8\mu \text{m}$. Bottom left: corresponding dark noise characteristics. Plain lines are theory, while markers are experiment.

Figure 3

Top right: dark current model and measurements for the QCD detecting at $15\mu \text{m}$. Bottom left: corresponding dark noise characteristics. Plain lines are theory, while markers are experiment.

Figure 4

Top right: dark current model and measurements for two pv-QWIPs detecting at $10\mu \text{m}$. Bottom left: corresponding dark noise characteristics. Plain lines are theory, while markers are experiment. Sample 1 differs slightly from sample 2 in the design of the capture well.

Figure 5

Top right: dark current model and measurements for the pc-QWIP detecting at $17\mu \text{m}$. Bottom left: corresponding dark noise characteristics. Plain lines are theory, while markers are experiment.

Figure 6

Noise current densities without reduced correlations (dashed) and with reduced correlations (plain). While at low bias correlations tend to decrease the noise, at high bias they amplify fluctuations.