exhibit 10. 1 international assignment letter december 18, 2012 mr. david w. keck 11754 windemere dr missoula, mt 59804 dear david, this letter ( referred to as the “ assignment letter ” ) outlines the terms and conditions of your international assignment ( the “ international assignment ” ) pursuant to which you are to be seconded to gt advanced technologies limited, a subsidiary of gtat corporation ( collectively, “ gtat ” ). this assignment letter, together with any additional documents, agreements or provisions that may be referenced herein, including your employment agreement with gtat, constitutes the entire understanding of your international assignment in hong kong. if questions should arise concerning any provision listed in this assignment letter or any subsequent revisions to policies applicable to employees on international assignment, you are urged to consult with your contacts for human resources matters : ada lui and pat moquin. please note that the terms and content of this assignment letter are confidential and may not be directly or indirectly disclosed by you to any other party other than your direct manager, family or legal representation ( as may be applicable ). gtat will not guarantee the term of any international assignment. your international assignment and overall employment with gtat will continue as long as mutually acceptable. the terms and conditions of this assignment letter will be governed by the laws of the state of montana, usa. this assignment letter does not create a contract of employment between you and gtat for any specified period. your employment with gtat shall continue to be subject to the terms and conditions of your employment agreement. effective date of assignment : january 1, 2013 title : executive vice president and general manager polysilicon and photovoltaic equipment assignment location : hong kong reporting : directly to dan squiller, president crystal growth systems and worldwide operations expected international assignment term : three ( 3 ) years beginning on effective date exhibit 10. 1 international assignment letter december 18, 2012 mr. david w. keck 11754 windemere dr missoula, mt 59804 dear david, this letter ( referred to as the “ assignment letter ” ) outlines the terms and conditions of your international assignment ( the “ international assignment ” ) pursuant to which you are to be seconded to gt advanced technologies limited, a subsidiary of gtat corporation ( collectively, “ gtat ” ). this assignment letter, together with any additional documents, agreements or provisions that may be referenced herein, including your employment agreement with gtat, constitutes the