Investigation of trap levels in HgCdTe IR detectors through low frequency noise spectroscopy

Abstract

Low frequency noise spectroscopy is a valuable tool for studying narrow gap semiconductor materials and devices. In the paper, the method of traps investigation with low frequency noise spectroscopy was presented, together with quantitative analysis of the results obtained for highoperating-temperature, fast response, Hg 1−x Cd x Te mid-wavelength infrared detectors. The hole trap levels in these devices are Cd-content independent and take the value E T ≅140 meV or E T ≅40 meV. The level at E T ≅140 meV was found for almost all tested detectors. The level around E T =40 meV was found in two samples. Apart from the hole traps, three electron traps were also found. Their energy levels follow the trend lines E T =0.35E g (x) and E T =0.75E g (x). All trap energies are consistent with the results reported in the literature for Hg 1−x Cd x Te devices.

Deep levels analysis in wavelength extended InGaAsBi photodetector

“…LFN includes 1/f noise and generation -recombination (G-R) noise, where the PSD of 1/f noise is inversely proportional to frequency and the G- corner frequency where Lorentzian appear as symmetric peak . In a n-type material, we have time constant [34]:…”

“…In addition, time constant τ i can be written as τ i =1/(2πf c ), f c is corner frequency where Lorentzian appear as symmetric peak . In a n-type material, we have time constant [34]:…”

“…In addition, time constant τ i can be written as τ i =1/(2πf c ), f c is corner frequency where Lorentzian appear as symmetric peak . In a n-type material, we have time constant [40]: Where v th is electron's thermal velocity, σ is capture cross section, E T is deep level position, E c and N c are the conduction band edge and effective density of states, v th and N c are T 1/2 , T 3/2 dependent, respectively. From the Arrhenius plot of ln(τT 2 ) versus 1000/T, the energy level and capture cross section of the deep levels can be obtained based on the slope and intercept.…”

Trap parameters in the infrared InAsSb absorber found by capacitance and noise measurements

“…Then, the extraction of trap parameters (ΔE t , σ) can be done from the Arrhenius plot of the corner frequency f c (T)=e max (T)/2π=1/2πτ(Τ), in a way similar to DLTS method. The measurements setup for LFNS and the methodology of finding relaxation time τ(Τ) from measured psd S i ( f, T) at different temperatures have been described in [22,23].…”

High frequency response of LWIR HgCdTe photodiodes operated under zero-bias mode

“…HgCdTe heterostructure photodiodes also exhibit subnanosecond time constants while operate under reverse bias (Madejczyk et al 2017;Grodecki et al 2017). However, non-equilibrium conditions lead to an excessive low frequency 1/f noise that extends up to MHz range (Ciura et al 2016).…”