Charge transport features of CdTe-based X- and γ-ray detectors with Ti and TiOx Schottky contacts

CdTe X/γ-ray Detectors with Different Contact Materials

“…The width of the SCR (Equation ( 4)) was calculated at the concentration of uncompensated acceptors N = N a −N d = 5 × 10 10 cm −3 as it was estimated for CdTe single crystals produced by Acrorad [20][21][22][23][24][25][26]. The temperature dependences of the bandgap E g (T) = 1.608 -4.52 × 10 −4 × T (eV), holes mobility µ p = 4 × 10 5 × T −3/2 (cm 2 /V•s), and resistivity of CdTe were taken into account [15,16,20].…”

“…Figure 9 presents a comparison of the calculation results using Equations ( 1)-( 4) (solid lines) and experimental data (symbols). It should be emphasized that the calculations were performed at the concentration of uncompensated acceptors N = N a -N d = 5 × 10 10 cm −3 as it corresponded to CdTe single crystals produced by Acrorad and the ionization energy of the generation-recombination center was accepted as E t = 0.67 eV [20][21][22][23][24][25][26]. The computed results exhibited that the lifetimes τ n0 of electrons and holes τ p0 were such critical parameters determining the reverse current values in the I-V characteristics.…”

“…The features of the CdTe-based X/γ-ray detectors with different contact materials were studied in details earlier [ 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The capabilities of the developed detectors to operate for long time without deterioration of their functional parameters were shown and analyzed.…”

“…During the last two decades, we have widely used semi-insulating CdTe semiconductors, produced by Acrorad for material characterization [15][16][17] and elaboration of both Schottky diode-type [18][19][20][21][22][23][24][25][26][27] and M-p-n structured [27][28][29][30][31][32][33][34] X/γ-ray detectors. Using different metals (Ni, Cr, In, Al, and Au) for electrodes to form appropriate Schottky and ohmic electrical contacts or employing laser-induced doping of a thin CdTe layer with In, we have obtained high performance diode-type X/γ-ray detectors with excellent roomtemperature energy resolution.…”

“…We have recently studied other electrode materials (graphene, metal oxides and nitrides) different from metals used before and developed the techniques to employ them for the formation of Schottky and ohmic electrical contacts to Acrorad's semi-insulating CdTe crystals [21][22][23][24][25][26]. We have interested to develop this trend, in particular using molybdenum oxide as a promising material for ohmic contact formation [35][36][37][38][39][40].…”