Download the excel file by using download option Please help me

Need Help
1

I have used the phpspredsheet to generate the Excel file. but all works perfect but i want to browser donwload so i have set following code but the file generate the encode with buggy characters.

header('Content-Type: application/vnd.openxmlformats-officedocument.spreadsheetml.sheet');
    header('Content-Disposition: attachment; filename="' . $filename . '"');
    header('Cache-Control: max-age=0');
    $writer = \PhpOffice\PhpSpreadsheet\IOFactory::createWriter($spreadsheet, 'Xlsx');
    $writer->save('php://output');

output:: like �QĿi!��K�y3�J<���Z1�0?Y�L%zV