Crystal growth and characterization of Cd0.8Mn0.2Te using Vertical Bridgman method

By Vertical Bridgman method, several Cd0.8Mn0.2Te (CdMnTe) ingots were grown. The structure and crystallinity of the ingots were evaluated by X-ray powder diffraction and double-crystal rocking curve measurement and etch pits density (EPD) measurement. The results showed a pure cubic zinc blende structure throughout the ingots with the full width at half maximum (FWHM) of 40–70 arcsec and EPD of (6–8) × 104 cm−2, indicating a high crystalline perfection. The Mn concentration distribution along the axial and radial direction of the ingots was measured by inductively coupled plasma atomic emission spectrometer (ICP-AES). The segregation coefficient keff for Mn along the axis of the ingots is determined to be 0.95, and the radial variation of Mn concentration is within 0.002. Current–voltage (I–V) measurement reveals that sputtered Au film can form good ohmic contact to CdMnTe wafer and all the wafers of the as-grown crystals have the resistivity within (1–4) × 106 Ω cm. IR transmission measurement in the wave number region from 4000 to 1000 cm−1 exhibits that the IR transmittance of CdMnTe wafers is 50–55%, which is close to the theoretical value.