2.20 Size effects in thin films of cadmium arsenide

Semiconducting Compounds of the AII BV Group

“…The resistivity and Hall mobility fo r crystalline films are constant below about 250oK; i1H � T-3 / 2 with increasing temperature (117,120). For specially prepared, very thin films of Cd3As2 (d = 200-2000 A) obtained at ts � 170-180°C, the mobilities reach,!d values up to 0.2 m 2 fV-sec and quantum size effects were observed (131) (Figure 8). The oscillation period determined from Figure 8 (�Lex p � 100 A) is in satisfactory agreement with �Ltheor � 80 A calculated from the fo rmula �L = nh(2rn* x EFr 1/ 2 where E F = 0.12 eV and rn* = 0.05 rno as given in (92).…”

“…The electrical and mechanical properties of polycrystalline Cd3As2 films offer an opportunity for numerous applications in differentf i eIds Thin-film Hall generators made fr om Cd3Asz have been fabricated and their fundamental parameters have been examined (119,122,123). The DC sensitivity curves for these devices are linear for magnetic inductions up to 8 T and control currents of 100-150 rnA.…”

“…To obtain more stable and homogeneous films, several as-deposited films covered with a thin SiOx layer were subjected to a high temperature treatment and then annealed at 485°C (in this way the films experienced so·called protected recrystallization) (122,123). After such annealmg the resistivity of the film decreased by 1 to 2 orders in magnitude and the carrier mobility increased generally to the range 0.4-0.9 ml/V-sec (122) and (130). Special attention has been given to amorphous Cd3Asz films (117,125,(134)(135)(136)(137)).…”