let string = "tempValue&123"
let data = string.data(using: String.Encoding.ascii, allowLossyConversion: false)
guard let data = data else {
    return nil
}

let descriptor = CIDataMatrixCodeDescriptor(payload: data, rowCount: 1, columnCount: 1, eccVersion: CIDataMatrixCodeDescriptor.ECCVersion(rawValue: 0))
let inputParameter  = ["inputBarcodeDescriptor": descriptor]
let datafilter = CIFilter(name: "CIBarcodeGenerator", parameters: inputParameter)
let image = datafilter?.outputImage
print(image)