## 3 Results and Discussion
### Transport Properties along the Layers
Thus, the total mobility is \(\mu^{-1}=\mu_{FS}{}^{-1}+\mu_{BH}{}^{-1}\), where \(\mu_{BH}\) is the Brooks-Herring mobility for scattering with ionized impurities. Assuming that in the Brooks-Herring expression the effective concentration of screening carriers is equal to the concentration of free electrons, for the pristine sample we obtain the concentration of ions to be \(N_{\rm i}=7.35\times 10^{15}\) cm\({}^{-3}\), and that of compensating acceptors to be \(N_{\rm A}=(N_{\rm i}-n)/2=1.94\times 10^{15}\) cm\({}^{-3}\). This means that the pristine InSe crystal is not a highly compensated semiconductor. The main peculiarities of the intercalated crystals are the presence of extrema in the temperature dependences of \(R_{\rm H}\) and non-monotonous changes of \(\mu_{\perp\mathbb{LC}}\). In comparison to the pristine \(n\)-InSe sample, the Hall coefficient for the intercalated ones is higher. Starting from 80 K for sample 2 and after 110 K for sample 3, the \(R_{\rm H}\) values increase with temperature and take their maxima at 160 and 200 K, respectively. The low-temperature mobility of electrons along the layers becomes decreased after the first-time and repeated insertion of RbNO\({}_{3}\). For both intercalated samples, the mobility increases with increasing temperature and, in the high-temperature range, is nearly the same as in pristine samples. It should be noted that during the insertion of the ionic salt between the layers of \(n\)-InSe, the samples are simultaneously subjected to thermal annealing, as the intercalation is done at high temperatures. Usually, a vacuum treatment at 450-550 \({}^{\circ}\)C results in an increase of free carriers because of the dissociation of interlayer In inclusions that continues for 2 h [26]. However, at the conditions used for the intercalation (low temperature and duration), the effect of annealing on the electrical parameters is not determinative. The obtained dependences of the electrical characteristics for the intercalated crystals are typical for transport properties with two types of charge carriers contributing to the total conductivity \(\sigma=\sigma_{2}+\sigma_{3}\), with corresponding concentrations and essentially different \begin{table}
\begin{tabular}{c c c c c c c} \hline \hline \multirow{2}{*}{**Sample**} & \multicolumn{2}{c}{\(\sigma_{\perp\mathbb{LC}}\) **(Ohm\({}^{-1}\)-cm\({}^{-1}\))**} & \multicolumn{2}{c}{_n **(cm\({}^{-3}\))**} & \multicolumn{2}{c}{\(\mu_{\perp\mathbb{LC}}\) **(cm\(\cdot\)V\({}^{-1}\).s\({}^{-1}\))**} \\  & **80 K** & **300 K** & **80 K** & **300 K** & **80 K** & **300 K** \\ \hline
1 & 6.10 & 1.121 & \(3.85\times 10^{15}\) & \(7.61\times 10^{15}\) & 9905 & 919 \\
2 & 0.0837 & 0.142 & \(2.08\times 10^{15}\) & \(1.61\times 10^{15}\) & 251.3 & 549 \\
3 & 0.0313 & 0.0487 & \(2.00\times 10^{15}\) & \(8.04\times 10^{14}\) & 97.9 & 378 \\
4 & 5.91 & 1.328 & \(5.93\times 10^{15}\) & \(9.60\times 10^{15}\) & 6226 & 864 \\
5 & 4.72 & 1.531 & \(6.66\times 10^{15}\) & \(1.14\times 10^{16}\) & 4970 & 836 \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Electrical parameters along the layers of different \(n\)-InSe samples. mobilities. Within such a model, the Hall coefficient is given as a function of carrier concentration and mobility by the following expression:  
\[R_{H}=\frac{r_{2}n_{2}\mu_{2}^{2}+r_{3}n_{3}\mu_{3}^{2}}{e(n_{2}\mu_{2}+n_{3}\mu_ {3})^{2}} \tag{3}\]  
Here \(r_{2}\), \(n_{2}\), \(\mu_{2}\) and \(r_{3}\), \(n_{3}\), \(\mu_{3}\) are Hall factors, concentrations, drift, and Hall mobilities for two types of electrons. Assuming that \(r_{2}=r_{3}=1\) and the total concentration of electrons is constant (\(n_{2}+n_{3}=\text{const}\)), the parameter \(R_{\text{H}}\) reaches its maximum when the conductivities are the same (\(\sigma_{2}=\sigma_{3}\)).