Modification of the electrical properties in pure and doped GaSb by doping with Er and Yb

n-type Te doped Gallium antimonide, Te-doped-Er codoped GasSb and and Te-doped-Yb-codoped GaSb single crystals have been grown by using Liquid Encapsulated Czochralski. Carrier mobility, density and resistivity along the crystal have been obtained. The axial dopant composition has also been studied by analysing different wafers by Induced Coupled Plasma (ICP). From these measurements it is concluded that codoping with Er and Yb greatly reduces the mobility and increases the resistivity in both cases compared to simply Te doped GaSb. Secondary Electron Microscopy (SEM) and Energy Dispersive X-Ray (EDX) analysis have revealed Sb clustering in Er and Yb codoped Te-doped GaSb samples. These defects could be the responsible for the reduction of the carrier mobility and the increment in the resistivity. TPV cells, with size of 4 mm(2) have been developed in the Te-doped GaSb sample showing relatively high performance.