CARACTERIZAREA HETEROSTRUCTURILOR CdS/CdTe/Te CU AJUTORUL CARACTERISTICILOR CAPACITATE-TENSIUNE

Abstract

Thin Film CdS/CdTe heterojunctions were fabricated by close space sublimation at the substrate temperature 340 ± 5ºC and evaporator temperature 610oC± 5ºC. Capacitance-voltage characteristics in the region of temperatures 313 K – 363 K were measured. Was established that the capacitance of heterojunction CdS/CdTe/Te increases from 658 (cm2/pF)2, T=313 K to 1096 (cm2/pF)2, T=393 K. The width space charge region at room temperature is 7,4 μm, but at the tempera-ture of 393 K are 0,15 μm. In the above mentioned temperature region the potential contact barrier height decreases from 0,8 V at room temperature (293 K) up to 0,12 V at the temperature of 393K. The ionized-charge concentration profi le (NA-ND)is not constant, but it is increasing together with the enlarging of the depth of heterojunction and measure tem-perature, indicating to a high density of the states in the space charge region