3.1.3. Temperature Dependence

The temperature dependence of the strip current as a function of reverse-bias voltage is shown in Figure 6. From now on, only results obtained with the detector SM1 are presented. In order to perform this measurement, the device was attached to a Teflon circuit board using a silver conductive glue. Electrical contacts were established using 25 μm gold wire-bonding connections. Measurements were acquired, biasing up to 200 V the back contact with the Keithley 2410 source meter and reading the currents from the Keithley 6430 electrometer. Tests were carried out inside an environmental chamber, setting the temperature at 27 ◦C, 47 ◦C, 67 ◦C, 87 ◦C, and 107 ◦C, and monitoring it by means of a thermocouple placed near to the device. During each measurement, the temperature changes were monitored within ±0.1 ◦C. The current density was calculated considering a strip active area of 5 × 10−<sup>4</sup> cm<sup>−</sup>2.

**Figure 6.** Current and current density dependence from temperature in the range 27 to 107 ◦C.

Such a thermally activated process is described by the Arrhenius plot that, according to the emission theory, is expressed by

$$I = I\_0 \cdot \exp\left[\left(-\frac{E\_A}{kT}\right) \cdot \left(1 - \frac{T}{T\_0}\right)\right] \tag{2}$$

where *I*0is the saturation current, *T*0is the room temperature, and *E*A is the activation energy [5,25].

Figure 7 shows the Arrhenius plots of the leakage current as a function of 1000/*T* at four different reverse voltages, i.e., 50 V, 100 V, 150 V, and 200 V. The activation energy is given by the slope of linear fit of data. Values from 0.57 eV to 0.65 eV were calculated in the voltage range 50 V to 200 V. According to the literature, these values refer to major deep levels (*Z*1/2 center) within the bandgap [26–28].

**Figure 7.** Arrhenius plots of the leakage current (and current density) versus the reverse of temperature at four different voltages. The activation energy values are from 0.57 eV to 0.65 eV in the voltage range 50 to 200 V.

#### 3.1.4. Interstrip Resistance Measurements

Current–voltage measurements shown in previous sections refer to the characterization of single strips, considering that the measured current arrived only from the back contact of the device, and possible latent currents from adjacent strips were negligible. In order to determine the bias limit condition so that two adjacent strips can be considered isolated, we measured the interstrip resistance.

Interstrip resistance measurements were carried out by measuring the current between two consecutive strips, keeping the back contact at 100 V and the guard at 0 V. One of the two strips (microstrip 2 in Figure 8) is biased from −5 V to +5 V while the current of the other strip (microstrip 1 in Figure 8), kept at 0 V, is measured by an electrometer. We repeated the test on three couples of strips. The negative slope shown in Figure 8 is due to the application of the bias voltage to microstrip 2 while measuring the current at microstrip 1. The mean value of resistance between two adjacent strips of SM1 resulted in 5.3 TΩ.

**Figure 8.** Mean value of resistance between two adjacent strips.
